Blueberry Streusel Muffins

For the Muffin:
1/2 cup (57g) butter, room temperature
175g granulated sugar
250g all purpose flour
2 tsp baking powder
1/2 tsp sea salt
2 large eggs
1 tsp vanilla paste
1/2 cup milk
175g fresh blueberries

Streusel:
1/2 cup all purpose flour
1/2 cup light brown sugar
1/2 tsp cinnamon powder
2 tbs butter, room temperature

• First step: Make the streusel by combining all the streusel ingredients with hands or a spatula until well blended and crumbly. Cover the bowl with a plastic wrap and refrigerate until ready to use.
• For the muffin: In a bowl, combine the flour, baking powder and salt until well mixed.
• In a mixing bowl, beat the butter and sugar just for about 2 minutes, add in the eggs, one at a time. Add vanilla paste and beat for another minute.
• Preheat oven to 190 °C, prepare muffin tin, line it with paper liner.
• Gradually add the flour mixture alternating with the milk, fold with spatula just until well combined. Fold in the fresh blueberries, fold gently to avoid batter turning blue. 
• Take the streusel out from the refrigerator.
• Spoon the batter evenly into prepared muffin tin and sprinkle the streusel topping over the muffin batter, bake for about 25- 30 minutes or until a toothpick inserted in the middle comes out clean.