Heat frying pan over medium heat until hot, 3 minutes. Melt 2 tablespoons butter, cook and stir garlic until fragrant, 30 seconds.
Add 1 tablespoon butter and Brussels sprouts, cut-side down, cover and cook until golden brown, 4-6 minutes.
Flip Brussels sprouts, add 1 tablespoon butter. Cover and saute until other side is browned, about 3 more minutes.
Transfer to serving plate. Sprinkle with Parmesan cheese, salt and pepper.