1.) COAT 12 muffin cups generously with cooking spray.
2.) HEAT butter in large nonstick skillet over medium heat until hot. ADD broccoli, red pepper and onion; COOK 3 to 4 minutes, stirring occasionally. TRANSFER to large bowl. ADD bread and cheese; TOSS to mix.
3.) BEAT eggs, half-and-half, salt and pepper in medium bowl until blended. POUR over bread mixture; TOSS gently to coat. SPOON bread mixture into muffin cups. REFRIGERATE, covered, 1 hour or overnight.
4.) HEAT oven to 350°F. BAKE in center of oven until puffed, golden and knife inserted near center comes out clean, 20 to 25 minutes. LOOSEN stratas from sides of pans with thin knife.