Created by Christianna on December 6, 2014
Step 1: Prepare streusel topping: In a medium bowl, stir together brown sugar, flour and salt and cinnamon. With a pastry blender or two knives, cut in butter until mixture resembles large coarse crumbs; refrigerate until ready to use.
Step 2: Preheat oven to 350. 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.
Step 3: To make muffins: 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.
Step 4: Divide half the batter among prepared muffin cups. Top with half the streusel mixture, then remaining batter and top with streusel.
Step 5: Bake 25 to 30 minutes or until a toothpick inserted in center of a muffin comes out clean.
Step 6: Cool in pan 5 minutes, then transfer to a wire rack to cool completely.
Step 7: Dust with confectioner's sugar, if desired.