Apple Streusel Muffins recipe.

Ingredients
2 cups all-purpose flour
1 cup sugar
3 teaspoons baking powder
1 1/4 teaspoons ground cinnamon
1/2 teaspoon baking soda
1/2 teaspoon salt
1 cup sour cream
1/4 cup butter or margarine, melted
1 1/2 cups chopped, peeled tart apples
1/4 cup sugar
3 tablespoons all-purpose flour
1/4 teaspoon ground cinnamon
2 tablespoons cold butter or margarine

Directions
In a large bowl, combine dry ingredients. In another bowl, beat the eggs, sour cream and butter. Stir into dry ingredients just until moistened. Fold in apples. Fill greased or paper-lined muffin cusp two-thirds full.
For topping, combine sugar, flour and cinnamon. Cut in butter until mixture resembles coarse crumbs. Sprinkle a rounded teaspoonful over each muffin. Bake at 400 degrees F for 18-20 minutes or until a toothpick comes out clean. Cool for 5 minutes before removing from pans to wire racks. Serve warm.