Preheat waffle iron according to manufacturer's instructions. Place flours in large bowl along with sugar and baking powder. Mix well and set aside. Place egg whites in large bowl along with salt. Using an electric mixer, beat egg whites on high about 1 minute until fluffy and cling to bowl. Add milk and peanuts to bowl with flour mixture. Using wire whisk, whisk flour mixture into milk until just combined; there will be small lumps. Fold in 1/2 cup egg whites, using rubber spatula, until well-combined. Gently fold in remaining egg whites until just combined; batter should be light and fluffy. Coat inside of waffle iron with cooking spray. Place a heaping 1/2-cup mixture onto waffle iron, spreading it out slightly with rubber spatula. Top with 2 Tbsp. blueberries and close the lid. Cook for 3 to 4 minutes until waffle is cooked through but still soft to the touch. Transfer to plate. Repeat with remaining batter. Cool waffles completely and store in an air-tight container on the countertop for up to 3 days. To freeze, transfer cool waffles to large zipper lock bag and freeze for up to 3 months.
Makes 8 waffles.