Chunky Monkey Oatmeal Cookie Skillet

Featured in: Sweet & Calm Treats

ThisChunky Monkey Oatmeal Skillet brings together the beloved flavors of banana, chocolate, and walnuts in a warm, shareable dessert. The combination of mashed ripe bananas and semisweet chocolate creates pockets of sweetness throughout the tender oatmeal base, while chopped walnuts add a satisfying crunch. Baked in a cast-iron skillet, the edges turn golden and slightly crisp while the center remains soft and gooey—perfect for scooping straight from the pan. Whether you serve it plain or topped with vanilla ice cream, this 40-minute treat captures the essence of the classic Chunky Monkey combination in a cozy, homemade format that's ideal for gatherings or a special family dessert.

Updated on Sun, 08 Feb 2026 15:05:00 GMT
Freshly baked Chunky Monkey Oatmeal Cookie Skillet with melted chocolate chunks and ripe banana slices in a cast iron pan. Save
Freshly baked Chunky Monkey Oatmeal Cookie Skillet with melted chocolate chunks and ripe banana slices in a cast iron pan. | moonthyme.com

My friend texted me a photo of her blender mid-smoothie one afternoon—banana, chocolate, walnuts swirling together—and I thought, why hasn't anyone put this into a cookie form? That evening, I pulled out my cast-iron skillet and started experimenting, mashing bananas straight into brown sugar and melted butter, knowing the warmth would bring everything together. The kitchen smelled incredible within minutes, and by the time it came out golden and bubbly, I realized I'd stumbled onto something that felt less like a dessert and more like breakfast-for-dinner comfort.

I made this for a lazy Sunday brunch with my neighbor, who showed up unannounced with coffee, and we ate it still-warm with ice cream melting into every crevice while sitting on my porch. She asked for the recipe before she'd even finished her slice, which is always the sign something's a keeper.

Ingredients

  • Old-fashioned rolled oats (1 ½ cups): They give you chew and heartiness without being grainy—quick oats will make it too dense, so don't swap.
  • All-purpose flour (1 cup): Keep it measured level; too much and you'll get a dry brick instead of a tender skillet cookie.
  • Baking soda and baking powder (½ teaspoon each): These two work together to lift the batter just enough so it's fluffy-tender, not flat.
  • Salt (¼ teaspoon): It sounds small, but it wakes up the chocolate and banana flavors.
  • Unsalted butter, melted (½ cup): Melted butter creates a fudgier crumb than creaming does, which is exactly what you want here.
  • Brown and granulated sugar (⅓ cup each): The combination gives you depth from brown sugar plus structure from granulated—use both, not one or the other.
  • Egg (1 large): It binds everything while adding richness; room temperature works best if you remember, but cold will still work fine.
  • Vanilla extract (1 teaspoon): Real vanilla makes a noticeable difference in a simple recipe like this.
  • Ripe bananas, mashed (about 1 cup from 2 bananas): Look for bananas with a few brown speckles—they're sweeter and easier to mash, and their moisture is built-in leavening.
  • Semisweet chocolate chips (½ cup): They soften just enough without disappearing, and they keep the sweetness balanced.
  • Chopped walnuts (½ cup): Toast them lightly in a dry skillet first if you have five minutes; it wakes up their flavor in ways that surprise you.
  • Dark chocolate, chopped (½ cup, optional): Add this if you want richness that whispers rather than shouts.

Instructions

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Heat your oven and prepare the skillet:
Preheat to 350°F and grease your 10-inch cast-iron or oven-safe pan generously with butter or nonstick spray—the butter will actually bake into the edges and create this incredible golden crust you can't replicate in a regular pan.
Mix your dry team:
Whisk the oats, flour, baking soda, baking powder, and salt together in a medium bowl and set it aside, doing this first means you won't have any lumps of baking soda hiding in your final batter.
Cream your wet base:
Combine the melted butter and both sugars in a large bowl, stirring until creamy and slightly thick—you're building the flavor foundation here, so don't rush it.
Beat in the binding:
Add the egg and vanilla, stirring until everything looks pale and slightly fluffy, then stir in your mashed bananas until fully incorporated and no streaks of banana remain.
Fold gently:
Gradually add the dry ingredients to the wet mixture, folding with a rubber spatula until just combined—stop when you see a few flour streaks still visible, because overmixing toughens the crumb.
Scatter in the good stuff:
Gently fold in the chocolate chips, walnuts, and dark chocolate if using, taking care not to crush them as you fold.
Spread and bake:
Pour the batter into your prepared skillet and smooth it into an even layer—it will look thick, almost like cookie dough, which is exactly right.
Watch for golden edges:
Bake for 22 to 25 minutes until the edges turn a deep golden brown and a toothpick inserted in the center comes out mostly clean with maybe a few moist crumbs clinging to it (this is not underbaking, it's delicious). The center will firm up slightly as it cools.
Cool and serve:
Let it rest in the skillet for about 10 minutes—this lets the structure set just enough to hold its shape—then bring it straight to the table warm, ice cream optional but highly recommended.
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Store cookware, spices, and prep tools within reach to keep cooking organized and efficient.
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A warm, gooey Chunky Monkey Oatmeal Cookie Skillet topped with scoops of vanilla ice cream melting over the edges. Save
A warm, gooey Chunky Monkey Oatmeal Cookie Skillet topped with scoops of vanilla ice cream melting over the edges. | moonthyme.com

The moment I pulled this from the oven, my kitchen filled with this warm banana-chocolate-walnut smell that somehow felt both cozy and indulgent. My partner came downstairs wondering what smelled like a dessert adventure, and we ended up eating half of it that night, laughing about how we'd never need to buy cookies again.

Why Cast Iron Actually Matters Here

Cast iron isn't just a rustic choice—it distributes heat so evenly that your edges cook golden while the center stays tender and fudgy, something a regular metal baking pan struggles with. The side benefit is that bringing it straight to the table in the skillet looks intentional and impressive, even though you made it in 15 minutes of actual hands-on time.

Banana Ripeness Is Everything

I learned this the hard way on my first attempt: slightly underripe bananas made the mixture too stiff and the batter didn't spread evenly, while overripe bananas (the ones you'd normally throw away) turned into silk and added natural moisture and sweetness. Now I save those speckled bananas specifically for recipes like this one.

Variations and What Works

This recipe is genuinely forgiving when it comes to swaps, which is part of why it's become my go-to when the pantry is half-empty. I've made it with pecans instead of walnuts, swapped semisweet chocolate for milk chocolate, and even thrown in a handful of dried cherries when I found them hiding in the back of my cabinet.

  • For a vegan version, use coconut oil instead of butter and mix a flax egg (1 tablespoon ground flaxseed whisked with 2.5 tablespoons water) in place of the egg.
  • Pecans, almonds, or even macadamia nuts work beautifully if you don't have walnuts on hand.
  • A pinch of cinnamon or nutmeg adds warmth and depth without overpowering the banana and chocolate.
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Golden brown Chunky Monkey Oatmeal Cookie Skillet with rich dark chocolate and crunchy walnuts served directly in the skillet. Save
Golden brown Chunky Monkey Oatmeal Cookie Skillet with rich dark chocolate and crunchy walnuts served directly in the skillet. | moonthyme.com

This skillet cookie has become the dessert I make when I want something that feels homemade and special without the stress of piping, cooling, or perfectly even baking. Bring it warm to the table, let people serve themselves straight from the pan, and watch it disappear.

Recipe FAQ

What makes this skillet Chunky Monkey flavored?

The combination of mashed ripe bananas, semisweet chocolate chips, chopped walnuts, and optional dark chocolate creates the classic Chunky Monkey flavor profile inspired by the beloved ice cream variety.

Can I make this skillet ahead of time?

Yes, you can prepare the batter ahead and store it refrigerated for up to 24 hours before baking. The skillet also reheats beautifully in a warm oven or microwave.

How do I know when the skillet is done baking?

The edges should be golden brown and a toothpick inserted in the center should come out with just a few moist crumbs—avoid overbaking for the best gooey texture.

Can I substitute the nuts?

Absolutely—pecans work well as a direct substitute, or you can omit nuts entirely if needed. You might also try almonds or hazelnuts for different flavor notes.

What's the best way to serve this?

Serve warm straight from the skillet for the best experience. A scoop of vanilla or chocolate ice cream on top adds the perfect finishing touch, especially while still warm.

Is this suitable for vegetarians?

Yes, this dessert is vegetarian as written. For a vegan version, substitute butter with coconut oil and use a flax egg instead of the regular egg.

Chunky Monkey Oatmeal Cookie Skillet

A warm, shareable oatmeal skillet with banana, chocolate chips, and walnuts baked in a cast-iron pan for gooey, golden perfection.

Prep Time
15 min
Time to Cook
25 min
Total Duration
40 min
Created by Lydia Brooks


Skill Level Easy

Cuisine American

Portions 8 Serving Size

Diet Info Vegetarian Friendly

What You'll Need

Dry Ingredients

01 1½ cups old-fashioned rolled oats
02 1 cup all-purpose flour
03 ½ teaspoon baking soda
04 ½ teaspoon baking powder
05 ¼ teaspoon salt

Wet Ingredients

01 ½ cup unsalted butter, melted
02 ⅓ cup light brown sugar, packed
03 ⅓ cup granulated sugar
04 1 large egg
05 1 teaspoon pure vanilla extract

Chunky Monkey Add-ins

01 2 ripe bananas, mashed (approximately 1 cup)
02 ½ cup semisweet chocolate chips
03 ½ cup chopped walnuts
04 ½ cup chopped dark chocolate, optional

How to Make It

Step 01

Prepare the Baking Vessel: Preheat oven to 350°F. Grease a 10-inch cast-iron skillet with butter or nonstick spray.

Step 02

Combine Dry Components: In a medium bowl, whisk together oats, flour, baking soda, baking powder, and salt. Set aside.

Step 03

Blend Wet Base: In a large bowl, combine melted butter, brown sugar, and granulated sugar. Mix until well combined and creamy.

Step 04

Incorporate Egg and Banana: Beat in egg and vanilla extract, then stir in mashed bananas until fully incorporated.

Step 05

Fold Dry Into Wet: Gradually fold dry ingredients into wet mixture until just combined. Do not overmix.

Step 06

Add Mix-ins: Gently fold in chocolate chips, walnuts, and chopped dark chocolate if using.

Step 07

Transfer to Skillet: Spread batter evenly into prepared skillet.

Step 08

Bake Until Golden: Bake for 22 to 25 minutes, or until edges are golden and a toothpick inserted in center comes out mostly clean with a few moist crumbs remaining.

Step 09

Rest and Serve: Cool for 10 minutes before serving. Serve warm directly from skillet, optionally topped with vanilla ice cream.

Tools Needed

  • 10-inch cast-iron skillet or oven-safe baking pan
  • Medium and large mixing bowls
  • Whisk
  • Rubber spatula
  • Measuring cups and spoons

Allergen Details

Review every ingredient for allergens and ask a medical professional when unsure.
  • Contains wheat and gluten
  • Contains eggs
  • Contains milk products from butter and chocolate chips
  • Contains tree nuts, specifically walnuts

Nutrition Details (each serving)

These details are for reference only, and shouldn't replace healthcare advice.
  • Energy: 310
  • Fats: 15 g
  • Carbohydrates: 41 g
  • Proteins: 5 g