Preheat oven to 350 F. Line a 12 cup cupcake pan with cupcake liners. In a large bowl, whisk together flour, sugar, cocoa powder, salt, baking powder and baking soda. Add in eggs, milk, vegetable oil and vanilla extract. Whisk until smooth.
Evenly divide the cupcake batter between the prepared cupcake pan. Bake for 15-18 minutes. Let cool completely. For the chocolate buttercream frosting, in a large bowl using a hand mixer, beat softened butter with powdered sugar, milk, vanilla extract and cocoa powder until creamy.
Frost cupcakes and decorate with the m&ms and pretzel sticks.
