This peanut butter cookie cake is soft and chewy with a rich peanut butter flavor. It’s studded with chocolate chips and Reese’s Pieces, then finished with piped chocolate frosting — perfect for anyone who loves peanut butter. 
After making chocolate chip, double chocolate, and red velvet cookie cakes, I wanted a peanut butter version. This recipe yields a giant peanut butter cookie that’s thick, tender and chewy. I used real butter for flavor, a mix of brown and granulated sugar for chewiness and moisture, plus one whole egg and an extra yolk for added tenderness. Chocolate chips and Reese’s Pieces add pockets of sweetness while a simple chocolate frosting is piped around the edge to finish.
The Perfect Peanut Butter Cookie Cake
If you’ve baked peanut butter cookies before, this will feel familiar. Use unsalted butter at room temperature, brown and white sugar, and creamy commercial peanut butter (do not use natural or homemade varieties that separate). The extra egg yolk improves texture — don’t substitute two whole eggs. Measure flour carefully: 1 1/3 cups all-purpose flour weighs about 166 grams for best results. If you don’t have a scale, whisk the flour, spoon into a measuring cup, and level it off.
Avoid overloading the dough with mix-ins. I recommend no more than 1 cup total of add-ins (I used 1/2 cup chocolate chips and 1/2 cup Reese’s Pieces). Too many mix-ins make slicing the finished cookie cake difficult.
You can bake the cookie cake in a 9-inch springform pan or a 9-inch pie plate. A springform pan makes it easy to remove the outer ring and transfer the cake to a serving plate; if using a pie plate, serve directly from the pan. The included chocolate frosting is enough to pipe around the edge, with a little leftover if you want to add a small message. If you prefer more peanut butter, swap in a peanut butter buttercream and divide it as desired.
This cookie cake delivers strong peanut butter flavor, a chewy crumb and lots of nostalgia — ideal for birthdays or any time you want something less fussy than a layer cake. Soft, easy, and packed with Reese’s Pieces, it’s a crowd-pleaser.
More peanut butter ideas to try: peanut butter chocolate chip cookies, peanut butter cheesecake bars, and peanut butter blondies.
Peanut Butter Cookie Cake
Cook: 25 mins |
Total: 45 mins |
Servings: 10 pieces
Equipment
- 9-inch springform pan (or 9-inch pie plate)
Ingredients
Peanut Butter Cookie Cake
- 1/2 cup unsalted butter (112 g), softened
- 1/2 cup brown sugar (100 g), light or dark
- 1/2 cup granulated sugar (100 g)
- 3/4 cup creamy peanut butter (180 g), do not use natural
- 1 large egg
- 1 large egg yolk (discard the white)
- 1 teaspoon vanilla extract
- 1 1/3 cups all-purpose flour (166 g), measured properly
- 1/2 teaspoon baking powder
- 1/4 teaspoon salt
- 1/2 cup chocolate chips
- 1/2 cup Reese’s Pieces
Chocolate Frosting
- 1/2 cup unsalted butter (112 g), softened
- 2 cups powdered sugar (220 g)
- 1/4 cup cocoa powder (20 g)
- 1–2 tablespoons cream or milk, as needed
Instructions
Peanut Butter Cookie Cake
- Preheat oven to 350°F (180°C).
- Line the bottom of a 9-inch springform pan with parchment and lightly spray the sides, or lightly spray a 9-inch pie plate.
- In a large bowl, beat the butter, brown sugar and granulated sugar until fluffy.
- Mix in the peanut butter until smooth.
- Add the egg, the extra egg yolk, and the vanilla, mixing to combine.
- With the mixer on low, beat in the flour, baking powder and salt until just combined.
- Stir in the chocolate chips and Reese’s Pieces.
- Spoon the dough into the prepared pan and flatten into an even layer.
- Bake about 24–28 minutes, or until the top is golden. Remove and cool completely if adding frosting.
Chocolate Frosting
- Beat the butter until smooth.
- Add 1 cup powdered sugar first on low speed, then mix in cocoa powder.
- Continue adding the remaining powdered sugar about 1/2 cup at a time, alternating with a tablespoon of cream or milk until you reach the desired sweetness and pipeable consistency.
- If using a springform pan, unclamp the ring and lift the cake off the base onto a serving plate.
- Transfer frosting to a piping bag (a 1M tip works well) and pipe around the edges. Reserve extra for a message if desired.
Notes
- Pan size: Use a 9-inch springform or 9-inch pie plate. An 8-inch springform is too small for this batter.
- Peanut butter: Use commercial creamy peanut butter that does not separate. Natural or homemade peanut butter can cause inconsistent texture.
- Eggs: Use 1 whole egg plus 1 extra yolk (do not add two whole eggs).
- Mix-ins: Limit to about 1 cup total. Try chocolate chips, peanut butter chips, M&Ms or Reese’s Pieces.
- Storage: Store in an airtight container at room temperature up to 4 days. The cookie is softest on day one.
- Nutrition: Values are estimates per slice if cut into 10 pieces and all frosting is used.
Nutrition
Estimated per serving: Calories: 625 kcal; Carbs: 75 g; Protein: 9 g; Fat: 34 g; Saturated Fat: 17 g; Sugar: 57 g.