Preheat oven to 450 degrees F.

In a large, ovenproof skillet, warm olive oil over medium-high heat. Place brussels sprouts in one even layer, cut side down. Add garlic, then sprinkle lightly with salt and pepper. Allow brussels sprouts to cook undisturbed for about 2 minutes or until lightly browned on one side, then remove from burner.

Place the skillet on the middle rack of the oven. After 5 minutes, toss the vegetables by gently shaking the pan a little. After an additional 5 minutes, vegetables should be tender but not mushy. Remove from the oven. In a bowl, toss the brussels sprouts with balsamic vinegar and crushed red pepper. Serve immediately.