3 tbsp granulated sugar
3 tbsp dark brown sugar
1/2 cup plus 3 tbsp unbleached all purpose flour
2 cups (about 10 ounces) fresh blueberries
1 1/8 cups (8 ounces) plus 1 tsp sugar
2 1/2 cups (12 1/2 ounces) unbleached all porpose flour
2 1/2 tsp baking powder
1 tsp salt
2 larhw eggs
4 tbsp (1/2 stick) unsalted butter melted and cooled slighltly
1/4 cup vegetables oil
1 cup buttermilk
1 1/2 tsp vanilla extract
In a bowl stir together topping ingredients. Toss with fork until evenly moistened and mixture forms large chunks with pea -sixed pieces throughout.
Adjust oven rack to middle position and heat oven to 425 degrees. Spray standard muffin tin with nonstick cooking spray.
Bring 1 cup blueberries a nd 1 tsp sugar to simmer in small saucepan over medium heat. Cook mashing berries with spoon several times and stirring frequently, until berries have broken down and mixture is thickened and reduced to 1/4 cup cup, about 6 minutes. Transfer to small bowl and cool 10-15 minutes.
Whisk flour, baking powder, and salt together in large bowl.
Whisk remaining 1 1/8 cups sugar and eggs together in medium bowl until thick and homogeneousabout 45 seconds.
Slowly whisk in butter and vanilla until combined.
Using rubber spatula,fld egg mixture until just moistened. (Batter will be very lumpy with few spots of dry flour; do not overmix.)
Use a large spoon or ice cream scoop to divide batter equally among prepared muffin cups (batter should completely fill cups and mound slightly).
Spoon tsp of cooked berry mixture into center of each mound of batter.
Using chopstick or skewer,gently swirl berry ,filling into batter using figure-eight motion.
Sprinkle Streusel topping evenly over muffins.
Bake until muffin tops are golden and just firm,17-19 minutes, rotating muffin tin from front to back halfway through baking time.
Cool muffin tin for 5 minutes.Transfer to wire rack and cool 5 minutes before serving.