- tablespoon white sugar
- 1½ tablespoons light brown sugar
- ¼ teaspoon cinnamon
- ¼ teaspoon salt
- 1 tablespoon unsalted butter, melted
- 3 tablespoons all-purpose flour
- ¾ cup all-purpose flour
- ¼ cup light brown sugar
- 1 teaspoon baking powder
- 1/8 teaspoon baking soda
- ½ teaspoon cinnamon
- 1/8 teaspoon salt
- ½ cup sour cream
- 3 tablespoons unsalted butter, melted
- 1 egg
- 1 teaspoon vanilla Nonstick cooking spray
- MIX all the crumb topping ingredients together until it forms coarse crumbs. Set aside.
- COMBINE together the flour, brown sugar, baking powder, baking soda, cinnamon, and salt in a large bowl.
- WHISK the sour cream, butter, egg, and vanilla together in a separate bowl until well combined.
- MIX the wet ingredients into the dry until well combined.
- Preheat to 350°F (170°C)
- GREASE muffin cups with cooking spray and pour batter in until cups are ¾ full.
- SPRINKLE the top of the muffins with the crumb topping.
- PLACE the muffin cups you may need to work in batches.
- COOK the muffins at 350°F (170°C) for 12 minutes.