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
- 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 180 degrees. 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.