Step 1: Preheat oven to 350 degrees Fahrenheit. Line cupcake pan with paper liners.
Step 2: With an electric mixer, cream butter and sugar until fluffy. Add eggs one at a time and beat well. Add vanilla.
Step 3: In another bowl, sift together flour, baking powder, and salt. Add flour mixture to butter mixture alternately with milk. Gently fold in blueberries. Fill cupcake liners 3/4 full.
Step 4: Bake for 20 to 22 minutes or until a toothpick inserted in center of cupcakes comes out dry.
Step 5: Completely cool cupcakes in pan before frosting with lemon buttercream frosting.