Peanut Butter Banana Whoopie Pies
Also known as the Fat Elvis, these tender banana cakes are sandwiched with creamy peanut butter filling, fresh banana slices, and finished with an optional chocolate ganache for a decadent touch.
Quick dessert idea to use frozen bananas
This one-bowl whoopie pie batter is fast and simple, and it’s a great way to use up those overripe or frozen bananas in your freezer. No stand mixer required—just whisk and bake.
Optional ganache
The ganache is optional but elevates these handheld cakes into an elegant plated dessert. If you add fresh banana slices as extra filling, assemble just before serving so the fruit stays bright and doesn’t brown.
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Notes for Success
If you prefer not to make a buttercream, omit the buttercream addition in the peanut butter filling. The filling will be denser and more like a Reese’s Peanut Butter Cup, which works wonderfully as a rich sandwich filling.
Graham cracker crumbs in the peanut butter filling are optional. They add a more authentic peanut-butter-cup texture but are not essential. Adding buttercream makes the filling lighter and creamier but is optional.
Peanut Butter Banana Whoopie Pies
Ingredients
For the Whoopie Pie Cakes
- Mashed banana — 1 cup (≈240 g, about 2 medium bananas)
- Granulated sugar — 1 cup (200 g)
- Vegetable oil — ½ cup (120 ml)
- Ground flax — 1 tablespoon (mix with hot water)
- Hot water — 2½ tablespoons
- Vanilla extract — 2 teaspoons
- All-purpose flour — 2 cups (250 g)
- Baking powder — 1 teaspoon (5 g)
- Baking soda — 1 teaspoon (5 g)
- Ground cinnamon — ½ teaspoon
- Ground nutmeg — ¼ teaspoon
- Salt — ½ teaspoon (3 g)
For the Peanut Butter Filling
- Creamy peanut butter — 1 cup (260 g)
- Confectioners’ sugar — ½ cup (60 g)
- Salt — ¼ teaspoon
- Vanilla extract — 1 teaspoon
- Graham cracker crumbs (optional) — ¼ cup (28 g)
- Vegan buttercream (optional) — ½ cup
For the Icing (optional)
- Ganache — ¼ cup (use your preferred ganache recipe)
Instructions
- Prepare the flax egg: Mix the ground flax with hot water and whisk to a paste. Let it thicken for at least 5 minutes.
- In a large bowl, whisk together the oil, mashed banana, granulated sugar, vanilla, and the thickened flax paste until combined.
- Sift the flour, cinnamon, nutmeg, baking powder, baking soda, and salt. Add the dry ingredients to the wet mixture and whisk until smooth.
- Preheat the oven to 350°F (175°C). Chill the batter in the refrigerator briefly while the oven heats.
- Using a 1½-ounce scoop, drop batter onto a parchment-lined sheet pan, spacing scoops about 2 inches apart. Bake 12–15 minutes or until lightly golden and springy to the touch.
- Allow the cake rounds to cool completely before assembling.
- Make the peanut butter filling: Combine the peanut butter, confectioners’ sugar, salt, vanilla, and optional graham crumbs in a bowl. Stir or beat until smooth. Fold in optional buttercream at the end if using, to lighten the texture.
- Assemble whoopie pies by spreading a generous amount of filling on one cake round, topping with a second round. Add a fresh banana slice inside if desired and assemble just before serving to prevent browning.
- Optionally dip the assembled sandwiches in ganache or drizzle ganache over the tops for a finished look.
Video
Notes
Whoopie pies filled without fresh banana slices will keep 2–3 days at room temperature in an airtight container.
Freeze wrapped well for up to 1 month for longer storage.