Tnt-Blueberry Muffins

1/2 cup butter or margarine -- melted

2 1/2 cups all-purpose flour

1 cup sugar

2 1/2 teaspoons baking powder

1/4 teaspoon salt

1 1/2 cups fresh or dry-pack frozen blueberries

2/3 full. Bake in preheated

400 oven

20 minutes or until tops are golden and wooden pick inserted in center comes out clean. Remove from pan. Serve warm or cool on wire rack

1 tablespoon of vinegar to

1 cup of milk and let sit at least

5 minutes. OR-you can substitute buttermilk in place of soured milk.