Preheat and prep: preheat your oven to 375°F and line a 12-cup muffin pan with paper cups.
Stir together dries: use a fork to stir together the streusel flour, sugar, and cinnamon in a small bowl.
Mix in butter: add melted butter to dries and use a fork to blend until large crumbs form and there are no more dry patches in the mixture. Set aside.
TO MAKE THE MUFFIN BATTER:
Combine the dries: whisk together the flour, sugar, baking powder, baking soda, and salt in a mixing bowl until thoroughly combined. Use your fingers to break up any chunks of brown sugar you see.
Combine the wets: stir together melted butter, eggs, sour cream and vanilla in a separate small bowl until well combined and fairly smooth.
Mix wets and dries together: pour the wet mixture into the dry mixture and stir until batter is uniform and smooth, with no clumps remaining.
Fold in streusel: using a spatula, gently fold 1 cup (145g) of streusel into the batter until evenly distributed (busting up any really large chunks you see).*1
Divide and top: divide the batter evenly between prepped muffin cups (about a heaping ¼ cup of batter each). Generously sprinkle remaining streusel in clumps over top of each muffin to form an almost solid layer.
Bake: bake muffins for 17-19 minutes until golden brown, and the tops feel fully set in the center when gently pressed.
Cool, share, and enjoy: cool muffins for 10-15, then gently remove them from the pan. Allow muffins to cool fully or share with family and friends while warm for the tastiest sugar and spice breakfast, coffee break, or afternoon treat in town!
Notes
*1Streusel Tips: depending on how much your streusel has cooled, it may be easier or harder to keep it in clumps instead of dust.To make the clumps, squeeze a big chunk of streusel together in your hand, then gently break up that chunk over top of the pan to sprinkle smaller and larger clumps evenly over the surface of the muffin.
Storage: while I always recommend enjoying all baked goods when fresh (especially because these muffins are unbelievably tasty when warm from the oven!), they will keep for up to 5 days, in an air-tight container, at room temperature.
It’d mean so much to me if you could please give the recipe card a ⭐ rating on the site and leave a comment to help others find this sweet recipe! Xo, Jocelyn @ Mint+Mallow