Chunky Monkey Oatmeal Skillet (Print Version)

Warm banana chocolate walnut skillet baked in cast iron for sharing

# Components:

→ Dry Ingredients

01 - 1 1/2 cups old-fashioned rolled oats
02 - 1 cup all-purpose flour
03 - 1/2 teaspoon baking soda
04 - 1/2 teaspoon salt
05 - 1/2 teaspoon ground cinnamon

→ Wet Ingredients

06 - 1/2 cup unsalted butter, melted and slightly cooled
07 - 1/2 cup light brown sugar, packed
08 - 1/4 cup granulated sugar
09 - 1 large egg
10 - 2 teaspoons vanilla extract
11 - 2 medium ripe bananas, mashed (about 1 cup)

→ Mix-ins

12 - 1/2 cup semisweet chocolate chips
13 - 1/2 cup chopped walnuts
14 - 1/4 cup unsweetened shredded coconut (optional)

# Directions:

01 - Preheat oven to 350°F. Lightly grease a 10-inch cast-iron skillet with butter or nonstick spray.
02 - In a large bowl, whisk together the oats, flour, baking soda, salt, and cinnamon.
03 - In a separate bowl, combine the melted butter, brown sugar, and granulated sugar. Whisk until smooth.
04 - Add the egg and vanilla extract to the wet mixture and whisk well. Stir in the mashed bananas until fully combined.
05 - Pour the wet mixture into the dry ingredients and mix until just incorporated.
06 - Gently fold in the chocolate chips, walnuts, and coconut if using.
07 - Spread the dough evenly into the prepared skillet.
08 - Bake for 20 to 24 minutes, or until the top is golden and the edges are set but the center is still soft.
09 - Let cool for 10 minutes before serving warm. Serve slices directly from the skillet, optionally topped with ice cream.

# Expert Advice:

01 -
  • It bakes in under 25 minutes, so you go from craving to warm dessert faster than you'd expect.
  • Serving it directly from the skillet feels celebratory and means less cleanup than traditional cookies.
  • The texture is this perfect middle ground between soft and substantial, almost like a cake but with the heartiness of oats.
02 -
  • The banana is your leavening agent here—if you use unripe bananas, the dough won't rise as much and the cookie will be dense and gummy.
  • Pulling the skillet out when the center still looks slightly underbaked is non-negotiable; it continues cooking on the cooling rack and achieves that perfect soft-set texture.
03 -
  • If your bananas are bright yellow, let them sit for a day or two to develop those brown speckles—that's when they're at peak sweetness for baking.
  • Don't open the oven door before 18 minutes; cast iron retains heat so well that sudden temperature drops can deflate your rising cookie.
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