Rhubarb Blueberry Muffins

1/4 cup butter, softened
3/4 cup sugar
1 egg
1/4 cup sour cream
1 1/2 cups all-purpose flour
2 teaspoons baking powder
1 teaspoon salt
1/3 cup milk
1 cup fresh or frozen blueberries (do not thaw frozen berries before using)
1 cup fresh or frozen chopped rhubarb (measure rhubarb while still frozen, then thaw completely
before using; allow to drain but do not press out liquid)

Cream butter and sugar until smooth. Add egg and sour cream; mix well. In another bowl, combine flour, baking powder, and salt. Add flour mixture and milk alternately to creamed mixture, stirring well. Fold in blueberries and rhubarb. Fill foil-lined muffin cups 2/3 full; bake at 400*F for 20-25 minutes.

*These are fabulous muffins, but because there contain so much fruit, they will get soggy after a while. They're best right out of the oven; if you're going to save them, leave them out uncovered.