Peanut Butter Cookie Cake with M&M's
A soft, chewy peanut butter cookie baked in a cake pan and topped with colorful M&M's. This hybrid combines the texture of a thick cookie with the presentation of a cake, featuring creamy peanut butter, brown sugar depth, and peanut butter chips throughout. Serve warm or at room temperature for desserts, celebrations, or casual gatherings. The trick here is underbaking slightly to maintain that tender center while the edges turn golden.
Ingredients
- 1 ½ cups all-purpose flourgluten-free 1-to-1 flour1:1dietarygluten-free
may affect chew slightly
- ½ teaspoon baking soda
- ¼ teaspoon coarse kosher salt
- ½ cup unsalted butter, softened
- ¾ cup creamy peanut butter
- ¾ cup light brown sugar, packed
- ¼ cup white granulated sugar
- 1 large egg, room temperature
- 1 teaspoon vanilla extract
- 1 cup M&M's, dividedchocolate chips or candy-coated peanuts1:1textureadds peanuts
optional
- ½ cup peanut butter chips
Instructions
- 1
Preheat oven to 350 F and grease a 9-inch cake or tart pan with baking spray.
- 2
Combine flour, baking soda, and salt in a medium bowl using a fork or whisk.
- 3
In a large bowl, cream butter, peanut butter, both sugars, egg, and vanilla with an electric mixer on medium speed until well combined, scraping sides halfway through.
- 4
Add dry ingredients to wet mixture. Mix on low for 10 seconds, then increase to medium speed until just combined.
- 5
Fold in 1/2 cup M&M's and peanut butter chips with a rubber spatula.
- 6
Transfer dough to prepared pan and press evenly until flat using your hands.
- 7
Press remaining 1/4 cup M&M's into the top.
- 8
Bake until edges are just turning golden brown, 16-20 minutes; center should remain soft.
- 9
Cool on wire rack for 10 minutes, run a knife around edges to loosen, then invert onto rack to cool completely.
- 10
Frost cooled cake with drizzle or piped frosting as desired.
- 11
Top with remaining M&M's.
Tips
Do not overbake. The edges should just turn golden while the center stays soft and chewy for the best cookie cake texture.
Use room temperature egg and softened butter so they cream properly and incorporate air into the batter.
Press the M&M's into the top gently before baking so they stay in place rather than sinking.
Good to Know
Keep in an airtight container at room temperature for up to 3 days. Unfrosted cake keeps slightly longer.
Prepare dough, press into pan, and refrigerate unbaked for up to 24 hours. Bake when ready.
Serve at room temperature or slightly warm. Pairs well with cold milk or vanilla ice cream.
Common Mistakes
Do not overbake to avoid a dry, crumbly texture.
Do not skip the cooling period before frosting to avoid melting.
Do not skip scraping bowl sides to avoid lumps in the batter.
Substitutions
Gluten-Free Swaps
may affect chew slightly
General Alternatives
optional
FAQ
Can I use natural peanut butter instead of creamy?
Yes, use a 1:1 ratio, but stir the oil back in first. Natural peanut butter may make the cake slightly less dense and more crumbly.
What if my cake sinks in the middle after cooling?
This happens with underbaked centers. Ensure edges are golden and use an oven thermometer to verify temperature. A slightly sunken center is normal and adds to the chewy texture.
How long can I keep a frosted cake, and can I freeze it?
Keep frosted cake covered at room temperature for 2 days. Freeze unfrosted cake for up to 3 months wrapped tightly, or frosted cake for 1 month. Thaw at room temperature.