1/2 c. flour plus 1 1/2 c. separated
1/2 c. light brown sugar
2 T. sugar plus 2/3 c. separated
1/4 t. cinnamon
1/8 t. salt plus 1/2 t. separated
4 T. unsalted butter, cut into 8 pieces plus 10 T. separated
1 1/2 t. baking powder
1/2 t. lemon zest
1 1/2 t. vanilla
1 pt. fresh blueberries (frozen are too moist, do not use frozen)
Streusel topping: In a food processor, combine 1/2 c. flour, 1/2 c. light brown sugar, 2 T. sugar and 1/8 t. salt. Add in 4 T. butter cut into eight pieces one piece at a time. Blend until mixture is crumbly.
In a small bowl, blend together 1 1/2 c. flour and 1 1/2 t. baking powder. In a large bowl or mixer, combine 10 T. butter, 2/3 c. sugar, 1/2 t. salt and 1/2 t. lemon zest until creamy. Add in eggs one at a time. Blend until light and fluffy. Add in vanilla. Slowly blend in flour/ baking powder mixture. With spatula, gently fold in blueberries.
Pour blueberry mixture into a well greased 9 X 9 X 2 inch baking dish. Sprinkle with streusel topping. Bake at 350 degrees for 55 minutes or until deep golden brown.
May serve with vanilla bean ice cream or as a breakfast coffee cake.