Step 2

Mix buttermilk and oats in a medium bowl; let stand for 15 minutes.

Step 3

Whisk whole-wheat flour, all-purpose flour, wheat germ, baking powder, baking soda, salt, and cinnamon in a large bowl.

Step 4

Stir eggs, sugar, oil, and vanilla into oat mixture. Add wet ingredients to dry ingredients; mix with a rubber spatula just until moistened.

Step 5

Coat a waffle iron with cooking spray and preheat. Spoon in enough batter to cover three-fourths of the surface (about 2/3 cup for an 8-by-8-inch waffle iron). Cook until waffles are crisp and golden brown, 4 to 5 minutes. Repeat with remaining batter.