Makes 12 muffins
7 tablespoons (3/4 stick plus 1 tablespoon) unsalted butter, softened
3/4 cup sugar
2 large eggs
2 1/4 cups all-purpose flour
4 teaspoons baking powder
1/2 teaspoon salt
1 cup milk
1 1/2 teaspoons vanilla extract
1 1/2 cups fresh or dry-pack frozen unsweetened blueberries, unthawed
1/4 cup unbleached all-purpose flour
2 tablespoons granulated sugar
2 tablespoons packed light brown sugar
1/4 teaspoon ground cinnamon
2 tablespoons (1/4 stick) cold butter, cut into pieces
Preheat oven to 375º. Grease 12 cups of a standard 2 3/4-inch muffin tin with butter or butter-flavored nonstick cooking spray. In a medium bowl, cream the butter and sugar with an electric mixer. Add the eggs one at a time, beating well until light colored and smooth.
Combine the flour, baking powder, and salt in a small bowl. Add the dry ingredients to the creamed mixture in two equal portions, alternating with the milk and vanilla. With a rubber spatula, gently fold in the blueberries.
To make the Crumb Top: In a small bowl with a fork, or in a food processor, combine the flour, sugars, and cinnamon. Add the butter pieces and cut in just until coarse crumbs are formed.
Spoon the batter into each muffin cup, filling each cup level with the top of the pan. Divide the topping mixture over the tops of each muffin. Bake in the preheated oven for 20 to 25 minutes, or until golden and the tops are dry and springy to the touch. A cake tester will come out clean when inserted into the center. Remove from the oven and let stand 5 minutes. Remove each muffin with a small metal spatula. Freeze in plastic freezer bags up to 2 months.