1.In large bowl, whisk together flour, sugar, baking powder and salt.
2. Using electric mixer on low speed, mix in butter, milk, eggs and vanilla; beat on high speed until smooth, about 2 minutes.
3.Spoon into 12 paper-lined or greased muffin cups, filling about three-quarters full.
4Bake in centre of oven until cake tester inserted in centre comes out clean, about 18 minutes.
5. Transfer to rack; let cool completely.
Make-ahead: Store in airtight container for up to 1 day or freeze for up to 2 weeks.
Variation: Chocolate Cupcakes - Reduce flour to 1 cup and baking powder to 1/2 teaspoons Add 1/2 cup cocoa powder and 1 tsp baking soda to dry ingredients. Sift before adding butter and wet ingredients.