Description
A close-up of golden-brown blueberry streusel muffins, topped with a crumbly, buttery streusel and bursting with fresh blueberries.
Ingredients
For the Muffins:
2 cups all-purpose flour 
1/2 cup granulated sugar 
2 teaspoons baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt 
1/2 cup unsalted butter, melted 
2 large eggs 
1 cup buttermilk 
1 teaspoon vanilla extract 
1 1/2 cups fresh blueberries 
For the Streusel Topping:
1/3 cup all-purpose flour
1/3 cup brown sugar 
1/2 teaspoon cinnamon 
1/4 cup unsalted butter, softened
1/4 cup rolled oats
Instructions
Preheat Oven:
Preheat your oven to 375°F (190°C) and line a muffin tin with paper liners.
Prepare the Muffin Batter:
In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt. In another bowl, mix melted butter, eggs, buttermilk, and vanilla extract. Combine the wet and dry ingredients until just mixed, then gently fold in the blueberries.
Make the Streusel Topping:
In a small bowl, mix flour, brown sugar, and cinnamon. Cut in the softened butter until crumbly, then stir in the rolled oats.
Fill Muffin Tins:
Spoon the muffin batter into the prepared muffin tin, filling each cup about 2/3 full. Sprinkle the streusel topping generously over each muffin.
Bake:
Bake in the preheated oven for 18-20 minutes or until a toothpick inserted in the center comes out clean.
Cool and Serve:
Allow muffins to cool in the pan for 5 minutes before transferring to a wire rack. Enjoy warm or at room temperature! 
Tips:
For extra flavor, add a teaspoon of lemon zest 
to the batter.
You can substitute frozen blueberries if fresh ones are not available.