1. Preheat oven to 400°.
2. Lightly spoon flours into dry measuring cups; level with a knife. Combine flours, sugar, and baking soda in a large bowl; slowly stir in beer. Stir just until dry ingredients are moist. Stir in cheese and onions.
3. Spoon batter into an 8 x 4-inch loaf pan coated with cooking spray. Sprinkle oats over batter.
4. Bake at 400° for 40 minutes or until loaf sounds hollow when tapped. Let cool in pan 10 minutes. Remove from pan; cool completely on a wire rack.