Peanut Butter Cupcakes with Banana Buttercream - Cupcake Fanatic

Ingredients

• 1/4 cup (1/2 stick) unsalted butter, softened
• 1/2 cup smooth peanut butter
• 1/2 cup packed brown sugar
• 1 egg
• 2 tsp vanilla extract
• 1 1/4 cup all-purpose flour
• 1 tsp baking soda
• 1/4 tsp kosher salt
• 2/3 cup milk (I used plain unsweetened almond milk)
• 1 ripe banana, mashed (not overripe!)
• 1/2 cup (1 stick) unsalted butter, softened
• 1 tsp lemon juice
• 1/2 tsp vanilla extract
• pinch of salt
• 3 cups powdered sugar
• Peanut butter
• Finely chopped toasted peanuts