Grease twelve 2-1/2-inch muffin cups or line the muffin cups with paper bake cups; set aside.
In a bowl, beat sugar and butter with electric mixer until well combined. Beat in eggs, sour cream, and vanilla.
In another bowl, combine flour, baking powder, salt, baking soda, cinnamon, nuts, and vegetable or fruit. Stir into butter mixture until just moistened (batter should be lumpy).
Spoon into prepared muffin cups, filling each 2/3 full. Bake in a 400 degree F oven 20 minutes or until golden. Cool in muffin cups on a wire rack for 5 minutes. Remove; serve warm. Makes about 16.