2Preheat your oven to 350°F (175°C) and grease a 9-inch round cake pan.
In a medium bowl, whisk together the all purpose flour, baking powder, and salt. Set aside.
In a large bowl, cream together the butter and peanut butter until smooth and creamy.
Add the brown sugar and maple syrup to the butter mixture and beat until well combined.
Beat in the vanilla extract.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Pour the batter into the prepared cake pan and spread it evenly.
Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cake to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before serving.