1 1/2 cups flour
1/3 cup sugar
1 1/2 tsp baking powder
1/4 tsp baking soda
1/4 tsp salt
1/2 cup unsalted butter
1 cup sour cream
1 large egg
1 tsp vanilla
Preheat oven to 400 degrees F and line 12 muffin cups with paper liners. Into a bowl, sift together flour, sugar, baking powder, baking soda, and salt. Melt butter and in a small bowl whisk together with sour cream, egg, and vanilla. Stir butter mixture into flour mixture until just combined. Add in desired mix-ins.
Divide the batter among muffin cups (this batter is thick and will not run easily like other muffin batters) and bake in middle of oven until golden and a tester comes out clean, about 20 minutes.
Mix-in ideas: berries, chocolate chips, diced bananas, crushed pineapple, coconut, walnuts, almonds, pecans, peaches, apples. WHATEVER is in the fridge or cupboard.
