Combine first 6 ingredients; set aside.
Coat a small nonstick skillet with cooking spray, and place over medium-high heat until hot. Add red bell pepper, broccoli, and mushrooms; sauté until tender.
Add egg mixture to pan; cover and cook over medium-low heat 8 to 10 minutes or until set. Remove from heat; top frittata with alfalfa sprouts, and sprinkle with cheese. Cover and let stand 3 to 5 minutes or until cheese melts. Cut into 4 wedges, and serve immediately.