Preheat oven to 350°F (175°C).
Mix the dry cake ingredients in one bowl and the wet ingredients in another.
Combine until just mixed.
Divide the batter evenly between four lined 6-inch cake pans.
Bake for approximately 18–25 minutes, or until a toothpick inserted into the centre comes out clean. Cool completely.
Mix the Greek yogurt, peanut butter powder, peanut butter and creamed honey until smooth.
Divide the frosting in half and mix the cocoa powder into one half.
Layer the cooled cakes with frosting between each layer. Cover the outside and pipe decorative borders with the remaining frosting.
Refrigerate until ready to serve.
