Jam Filled Banana Cupcakes - Cupcake Fanatic

Ingredients

• 2 medium ripe bananas, mashed (about 1 cup)
• 1/2 cup buttermilk
• 4 tablespoons butter, melted
• 1 egg
• 1 teaspoon vanilla
• 1 cup all-purpose flour
• 3/4 cup sugar
• 1/4 teaspoon cinnamon
• 1/2 teaspoon baking soda
• 1/4 teaspoon baking powder
• 1/8 teaspoon salt
• 3/4 cup grape jam, or preferred flavor
• 8 tablespoons (1 stick) butter, softened
• 1/2 cup creamy peanut butter
• 3 cups powdered sugar
• 1/4 cup milk, plus more if needed