Preheat the oven to 350F. Line muffin tin with liners; set aside.
Beat sugar, butter, and vanilla in a large bowl on medium speed for about 3 minutes. Add eggs making sure to beat well.
Spoon flour lightly into a measuring cup. Use a knife to level the flour. Mix flour, cocoa, baking soda, and salt with a whisk until well mixed.
Alternately add flour mixture to sugar mixture with milk. Mix well after each addition. DO NOT OVERMIX!
Pour cupcake batter into liners and bake for 22 minutes or until toothpick comes out clean. Cool completely before frosting.