Spent Grain Waffles

1. Combine whole wheat flour, all-purpose flour and baking powder; sift. Add sifted flours to large bowl; stir in sugar and salt.
2. In a separate bowl, combine milk and buttermilk. Whisk yolks from separated eggs and add to milk mixture. Slowly stir in melted butter and oil.
3. In large mixing bowl, whip egg whites to medium peaks. While whites are whipping, gently mix dry ingredients, spent grain flour and milk mixture using well method; batter can have a few dry lumps.
4. Fold whipped egg whites into batter one-third at a time until just incorporated, do not overmix.
5. Using approximately 2/3 cup batter per waffle, bake waffles in waffle maker. Serve warm, topped with fruit and yogurt.