Chunky Monkey Oatmeal Cookie Skillet

My cast-iron skillet sat on the counter one Sunday morning, and I was staring at three overripe bananas wondering what to do with them. A friend had just raved about Chunky Monkey smoothies the week before, and suddenly I thought—why not bake that flavor into something warm and shareable? The result was this golden oatmeal cookie skillet, and it became the kind of dessert you bring straight to the table still sizzling, letting everyone dig in with a spoon while it's still melting.

I baked this for my book club last month, and what started as dessert turned into people lingering at the table, passing around the warm skillet long after the meeting should have ended. Someone even scooped a second serving before the first one cooled down, which felt like the highest compliment possible.

Ingredients

• Old-fashioned rolled oats (1½ cups): They give you that signature chewy texture and nutty flavor that makes oatmeal cookies worth eating in the first place.
• All-purpose flour (1 cup): Just enough structure to hold everything together without making it dense or cake-like.
• Baking soda and baking powder (½ teaspoon each): Work together to give you that light, tender crumb that spreads slightly at the edges.
• Salt (¼ teaspoon): Brings out the chocolate and banana flavors so nothing tastes one-dimensional.
• Unsalted butter, melted (½ cup): Melted butter distributes evenly and creates a more tender cookie than creaming would.
• Brown and granulated sugar (⅓ cup each): The combination gives you depth and slight caramelization at the edges.
• Large egg (1): Binds everything and adds richness without overwhelming the banana flavor.
• Pure vanilla extract (1 teaspoon): Choose real vanilla—it's the quiet backbone that makes every bite feel more sophisticated.
• Ripe bananas, mashed (2, about 1 cup): They should be spotted and soft enough that they practically mash themselves; this is where the moisture and sweetness come from.
• Semisweet chocolate chips (½ cup): They soften just enough in the heat to be indulgent without overpowering the oatmeal base.
• Chopped walnuts (½ cup): Toasting them first brings out their flavor, though raw works fine if you're short on time.
• Chopped dark chocolate, optional (½ cup): If you add this, you get those little pockets of extra richness that make people ask for the recipe.

Instructions

Heat your oven and prep the pan:

Set your oven to 350°F and grease your 10-inch cast-iron skillet generously with butter or spray—this is not the time to skimp because the edges will thank you later.

Combine the dry team:

In a medium bowl, whisk together the oats, flour, baking soda, baking powder, and salt, then set it aside and don't touch it yet.

Build the wet base:

In a larger bowl, stir the melted butter with both sugars until they're combined and sandy-looking, then the mixture will start to feel a little creamy.

Add the egg and banana:

Beat in the egg and vanilla, watching as it gets lighter and slightly fluffy, then fold in your mashed bananas until there are no streaks of white left.

Fold everything together gently:

Pour the dry ingredients into the wet mixture and fold with a spatula just until combined—the moment you can't see flour streaks anymore, you're done, because overmixing makes things tough.

Add your chocolate and nuts:

Gently fold in the chocolate chips, walnuts, and dark chocolate if you're using it, keeping everything loose and casual.

Transfer to the skillet:

Spread the batter evenly across your hot skillet, smoothing the top with the back of a spoon so it bakes level.

Bake until golden:

Slide it into the oven for 22 to 25 minutes—you want the edges to turn golden and a toothpick in the center to come out with just a few moist crumbs clinging to it.

Cool briefly, then serve:

Let it sit for about 10 minutes so the structure sets, then bring it straight to the table in that beautiful skillet and let people serve themselves warm.

Save to Pinterest

There's something about a warm dessert that people remember longer than a plated one. This skillet became the thing my neighbors mentioned weeks later, asking if I'd make it again for their dinner party.

Why This Skillet Works

Cast iron distributes heat evenly, which means your edges bake golden without the center staying raw. It also holds warmth beautifully, so dessert stays warm longer even after it leaves the oven. The one-pan method makes it feel less like following a recipe and more like assembling something from your pantry.

Making It Your Own

This recipe is forgiving enough to invite customization. I've swapped walnuts for pecans on days when that's what I had, and dried cherries sprinkled on top add brightness you wouldn't expect. For a vegan version, coconut oil replaces butter and a flax egg (1 tablespoon ground flaxseed mixed with 2.5 tablespoons water) stands in for the chicken egg without anyone noticing the difference.

Serving and Storage Tips

This skillet is best enjoyed warm, ideally with a scoop of vanilla or chocolate ice cream melting into the still-hot cookie. It keeps for a few days covered loosely on the counter, though honestly it never lasts that long in my kitchen.

• Reheat a slice in the microwave for 20 seconds if you want it warm again the next day.
• Vanilla ice cream melts into the warm cookie better than any topping could.
• Serve it straight from the skillet if you're showing off—it looks more impressive that way.

Save to Pinterest

This recipe turned a quiet Sunday into something worth remembering, and it might do the same for you. The magic isn't in fancy technique—it's in bringing people together with something warm and real.

Recipe Q&A

→ Can I make this skillet vegan?

Yes, substitute the butter with melted coconut oil and replace the egg with a flax egg. Combine one tablespoon ground flaxseed with two and a half tablespoons water, let it sit for five minutes until gelatinous, then use it in place of the egg.

→ What other nuts work in this skillet?

Pecans make an excellent alternative to walnuts and add a buttery richness that complements the banana and chocolate flavors. You could also try hazelnuts or almonds depending on your preference.

→ How do I know when the skillet is done baking?

The edges should be golden brown and a toothpick inserted into the center should come out with just a few moist crumbs attached. The center will continue setting slightly as it cools, so avoid overbaking.

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

While possible, old-fashioned rolled oats provide better texture and hold up better during baking. Quick oats may result in a softer, more cake-like texture that lacks the satisfying chewiness of traditional rolled oats.

→ How should I store leftovers?

Cover the cooled skillet tightly with aluminum foil or transfer leftovers to an airtight container. Store at room temperature for up to three days. For longer storage, wrap individual portions and freeze for up to three months.

→ What adds the most flavor to this Chunky Monkey skillet?

The combination of very ripe mashed bananas provides natural sweetness and moisture throughout, while the mix of semisweet and dark chocolate chips creates layers of rich chocolate flavor. Toasting the walnuts lightly before adding them enhances their nutty taste.