Weigh or lightly spoon flour into dry measuring cups; level with a knife. Combine flour, wheat bran, and next 3 ingredients (through salt) in a large bowl, stirring with a whisk.
Melt butter in a small skillet over medium; cook 90 seconds or until browned and fragrant, swirling pan frequently. Combine butter, yogurt, sugar, vanilla, banana, and egg in a bowl. Add yogurt mixture to flour mixture, stirring just until combined. Divide batter evenly among 12 muffin cups coated with cooking spray. Bake at 375 degrees F for 22 minutes or until a wooden pick inserted in center comes out clean. Cool in pan 5 minutes. Remove from pan; cool completely on a wire rack.