4 eggs
1 cup white sugar
1 cup light brown sugar
1 cup vegetable oil
1 tsp. vanilla extract
zest of one lemon
2 cups all-purpose flour
2 cups whole wheat flour
1 tsp. salt
1 tsp. baking soda
2 cups sour cream
2 cups blueberries, divided
For streusel:
1/4 cup all-purpose flour
1/2 cup plus 2 tbsp. white sugar
1 tsp. cinnamon
4 tbsp. cold butter
Preheat oven to 400 degrees F. Grease 24 muffin cups or line with paper muffin liners.
In a large bowl, beat eggs. Gradually add sugars while beating. Continue beating while slowly pouring in oil. Stir in vanilla and lemon zest. In a separate bowl, combine the flours, salt and baking soda.
Stir dry ingredients into egg mixture alternately with sour cream. Gently fold in 1-1/2 cups of the blueberries. Scoop batter into prepared muffin cups. Place remaining blueberries on top of muffins and press them in slightly.
For the topping, combine the flour, sugar and cinnamon in a bowl. Cut in the butter with a fork or pastry blender until the mixture forms coarse crumbs. Sprinkle on top of muffins before baking.
Bake in preheated oven for 20-25 minutes.