Treat yourself to these yummy Coffee Cake Muffins with Cinnamon Crumb Topping ... they're perfect for breakfast or brunch!
Preheat oven to 350 degrees.
Whisk together granulated sugar, brown sugar, cinnamon, and salt.
Stir in butter.
Mix in flour, stirring until well combined. Set aside.
Spray a muffin tin with nonstick spray. Then line the pan with cupcake liners.
Whisk together flour, cornstarch, baking powder, baking soda, and salt in a large bowl.
In a separate bowl, whisk together eggs, sour cream, sugar, butter, and vanilla extract.
Add wet ingredients to dry ingredients, then fold together with a spatula until just combined. Do not over mix.
Fill cupcake liners 2/3 full with batter. Do not overfill; you should have 16 muffins total.
Crumble crumb topping over muffins, gently pressing it into the batter.
Bake muffins for 15 to 20 minutes, or until a toothpick inserted in the center comes out clean. (Bake the muffins in batches, if needed.)
Let muffins cool for 10 to 15 minutes before serving.
While muffins are cooling, whisk together powdered sugar, milk, and vanilla extract until smooth.
Drizzle glaze over muffins, then serve. Enjoy!
Store leftover muffins in an air-tight container or freeze until ready to eat.