01 - 
                Set the oven to 350°F (175°C). Coat two 9-inch round pans with grease and sprinkle with flour.
              
              
              
                02 - 
                In a mixing bowl, combine 1 1/2 cups flour, 1 tsp baking powder, 1/2 tsp baking soda, and 1/4 tsp salt using a whisk.
              
              
              
                03 - 
                Beat 1/2 cup butter and 1/2 cup peanut butter together in a large bowl until it’s smooth and light.
              
              
              
                04 - 
                Slowly mix in 1 cup sugar, beating until fluffy. Add eggs one after the other, mixing well each time. Stir in 1 tsp vanilla extract.
              
              
              
                05 - 
                Mix the dry ingredients and 1/2 cup buttermilk into the peanut butter blend a little at a time, starting and ending with the dry ingredients. Combine gently.
              
              
              
                06 - 
                Carefully fold in 1 cup of M&M's.
              
              
              
                07 - 
                Pour the mix equally into the prepared pans. Bake for 25-30 minutes or until a toothpick pulled from the middle comes out without batter.
              
              
              
                08 - 
                Leave the cakes to rest in the pans for 10 minutes, then move them to a cooling rack to cool fully.
              
              
              
                09 - 
                For the frosting, mix 1/2 cup butter and 1 cup peanut butter in a large bowl until smooth and creamy.
              
              
              
                10 - 
                Add 2 cups powdered sugar gradually, mixing until smooth. Finish by beating in 1/4 cup heavy cream and 1 tsp vanilla until fluffy.
              
              
              
                11 - 
                Spread frosting over one cake layer. Place the second layer over it and cover the top and sides with more frosting.
              
              
              
                12 - 
                Sprinkle extra M&M's on the frosted cake to finish it off.