Chunky Monkey Oatmeal Skillet

My friend texted me a photo of her blender mid-smoothie one Tuesday afternoon—chunky monkey, she'd written, with a string of banana emojis. I was standing in my kitchen holding a overripe banana and thinking about how to use it before it turned completely brown, and something just clicked. Why not bake those flavors into something shareable, something that comes straight from the pan to the table still warm? This skillet became the answer, and now whenever I make it, the smell alone brings people running from other rooms.

Last spring I made this for a small dinner party, and one guest asked if I'd bought it from a bakery because the edges were so perfectly caramelized. I didn't correct her at first—I just smiled and watched her take another forkful. By the end of the meal, everyone wanted the recipe, and my cast-iron skillet became the hero of the evening in a way a regular cake never could have.

Ingredients

• Old-fashioned rolled oats: The foundation that gives this skillet its chewy, substantial texture—they soften as they bake but hold their shape, creating a cookie structure rather than a cake.
• All-purpose flour: Just enough to bind everything together without making it dense or tough; don't skip the gentle folding later.
• Baking soda and baking powder: A small amount of each works together to give you lift and a tender crumb, but resist the urge to add more or you'll lose that cookie density.
• Melted butter: Easier to work with than cold butter and creates a richer, more tender result than you'd get with oil alone.
• Brown and granulated sugar: The combination of both gives you depth and chewiness—the brown sugar adds molasses notes that play beautifully with banana and chocolate.
• Egg and vanilla extract: These bind the mixture and add subtle flavor that keeps the skillet from tasting one-dimensional.
• Ripe bananas: They should be spotted and soft, almost too soft to eat as fruit—that's exactly when they're perfect for baking and contribute natural sweetness.
• Semisweet chocolate chips and chopped dark chocolate: The chips melt slightly into the batter while the chopped chocolate holds its texture; using both keeps things interesting.
• Walnuts: Their slight bitterness balances the sweetness and adds a toasted, earthy note that keeps this from being one-note.

Instructions

Set your stage:

Heat your oven to 350°F and grease that cast-iron skillet well—butter works beautifully because it also adds flavor to the browned edges you're going to love. If you're using nonstick spray, just a light coat is enough.

Combine your dry team:

In a medium bowl, whisk the oats, flour, baking soda, baking powder, and salt together until everything is evenly distributed—no pockets of baking soda hiding anywhere. This step takes less than a minute and makes a real difference in how your final skillet bakes.

Build your wet base:

Pour the melted butter into a large bowl with both sugars and stir until the mixture looks creamy and slightly lightened—this doesn't require a mixer, just a wooden spoon and about thirty seconds of effort. You're essentially dissolving the sugars into the butter.

Bring in the egg and bananas:

Beat in the egg and vanilla, then add those mashed bananas and stir until they're fully incorporated into the mixture. The batter will look a bit loose right now, and that's exactly right.

Gentle fold, gentle hand:

Add your dry ingredients to the wet mixture and fold it together slowly with a rubber spatula until you don't see any streaks of flour—stop before it looks perfectly smooth. Overmixing develops gluten and makes everything tough; you want a slightly rustic texture at this stage.

Scatter your treasures:

Fold in the chocolate chips, walnuts, and dark chocolate (if using) with the same gentle hand, leaving some of the larger pieces visible in the batter for texture. This is where the magic starts to feel real.

Into the skillet:

Pour the batter into your prepared skillet and use your spatula to spread it into an even layer, making sure it reaches the edges. Don't press down hard—just guide it gently into place.

Bake with patience:

Slide it into the oven for 22 to 25 minutes, watching for the edges to turn golden brown while the center is still set but slightly soft to the touch. A toothpick inserted in the middle should come out with just a few moist crumbs—not wet batter, but not completely clean either.

Cool and serve:

Let the skillet rest for 10 minutes on the counter—this allows the structure to set slightly while it's still warm enough to serve beautifully. Bring it straight to the table in the skillet and serve with a spoon, ideally with vanilla or chocolate ice cream melting on top.

Save

There's something about serving food directly from the vessel it was cooked in that changes how people experience it. When my sister took her first bite from the warm skillet, she closed her eyes and said it tasted exactly like the feeling of Saturday morning—unhurried, generous, and just a little bit indulgent. That's the moment I knew this recipe had become something more than just a way to use overripe bananas.

Why Cast Iron Matters Here

The cast iron isn't just a tool—it's part of the experience. The skillet heats evenly, which means the edges caramelize beautifully without the center staying raw, and it keeps everything warm from the oven all the way to the table. If you don't have a 10-inch cast-iron skillet, an oven-safe ceramic or glass baking dish works, though you'll miss out on that gorgeous caramelized edge that people comment on.

Making It Your Own

This recipe is a framework, not a rulebook. I've made versions with pecans instead of walnuts, swapped in dried cherries for extra tang, and once I added a handful of shredded coconut because it was sitting on my counter. Each version felt distinct but still unmistakably itself—still warm and shareable and exactly what I wanted to bake that day.

• If you want a vegan version, use coconut oil instead of butter and make a flax egg with 1 tablespoon ground flaxseed mixed with 2.5 tablespoons water—let it sit for five minutes before adding it in.
• Dark chocolate lovers should chop up a small bar and use it alongside or instead of some of the chips for a more sophisticated flavor.
• Add a pinch of cinnamon or nutmeg to the dry ingredients if you want to echo banana bread's warm spice notes.

Storage and Keeping

This skillet keeps beautifully for three days covered loosely on your counter—it stays moist without becoming soggy, and you can reheat a slice in the microwave for 20 seconds to bring back that warm, fresh-baked feeling. Honestly though, it rarely lasts that long in my house.

Save

This skillet has become my answer to the question of what to make when someone's coming over and I want to feel like I baked something impressive without spending hours in the kitchen. It's the kind of dessert that tastes like you care, but doesn't ask for more than you're willing to give.

Recipe Questions & Answers

→ Can I make this skillet vegan?

Yes, substitute melted butter with coconut oil and replace the egg with a flax egg (1 tablespoon ground flaxseed mixed with 2.5 tablespoons water). Let the flax mixture sit for 5 minutes until gelatinous before adding to the batter.

→ Can I use quick oats instead of old-fashioned rolled oats?

Old-fashioned rolled oats work best as they provide better texture and hold up during baking. Quick oats may become too soft and mushy in the skillet.

→ How should I store leftovers?

Store cooled leftovers in an airtight container at room temperature for up to 2 days, or refrigerate for up to 5 days. Reheat individual portions in the microwave for 20-30 seconds or warm the entire skillet in a 350°F oven for 10 minutes.

→ Can I freeze this oatmeal skillet?

Yes, bake and cool completely, then wrap tightly in plastic wrap and foil. Freeze for up to 3 months. Thaw overnight in the refrigerator and reheat before serving.

→ What other mix-ins can I add?

Try adding dried cherries, shredded coconut, or peanut butter chips. You can also swap walnuts for pecans or add a sprinkle of sea salt on top before baking for a sweet-salty contrast.

→ Why is my center still gooey after the recommended baking time?

The center should remain slightly moist due to the bananas and chocolate. If it's excessively underbaked, continue baking in 3-5 minute increments until set. A toothpick should come out with moist crumbs, not wet batter.