Coffee Cake Muffins

From Martha Stewart

These moist and flavorful coffee cake muffins can be enjoyed any day of the week.

Makes 12 jumbo muffins

Ingredients
For the Muffins
        1/2 cup (1 stick) unsalted butter, room temperature, plus more for pans
        1 3/4 cups all-purpose flour (spooned and leveled), plus more for pans
        2 teaspoons baking powder
        1 teaspoon baking soda
        1 cup sour cream
        1 cup granulated sugar
        1 teaspoon pure vanilla extract
        2 large eggs
        Confectioners' sugar (optional)
   
For the Streusel Topping
        1 cup packed dark-brown sugar
        1 cup all-purpose flour, (spooned and leveled)
        1/2 teaspoon salt
        1/2 teaspoon ground cinnamon
        1/2 cup (1 stick) chilled unsalted butter, cut into small pieces

Method
Prepare streusel topping: In a medium bowl, stir together brown sugar, flour, and salt. With a pastry blender or two knives, cut in butter until mixture resembles large coarse crumbs; refrigerate until ready to use.
   
Preheat oven to 350°F. Prepare muffins: Butter and flour a jumbo 12-cup muffin tin (or two 6-cup muffin tins). In a small bowl, whisk together flour, baking powder, and baking soda; set aside.
   
Using an electric mixer on medium speed, beat together butter, sour cream, granulated sugar, and vanilla until light and fluffy. Beat in eggs, one at a time, until well combined. With mixer on low, beat flour mixture into butter mixture.
   
Divide half the batter among prepared muffin cups. Top with half the streusel mixture, then remaining batter, and top with streusel. Bake 25 to 30 minutes or until a toothpick inserted in center of a muffin comes out clean. Cool in pan 5 minutes, then transfer to a wire rack to cool completely. Dust with confectioners' sugar, if desired.