In a medium bowl, combine the eggs and sugar.
Whisk in the sour cream, oil, and vanilla.
Add in the flour, baking powder, and salt.
Stir until just combined.
In a small bowl, combine 1 cup blueberries with the 1 tbsp flour.
Add blueberries into batter and gently fold into mixture.
Spoon mixture evenly into each lined muffin cup, filling about 2/3.
Sprinkle the remaining blueberries on top of each muffin cup.
Sprinkle the streusel generously on top of each muffin cup.
Place pan into preheated oven and bake for about 20 minutes.
Remove from oven and allow to cool slightly before removing and enjoy!