Place butter in a medium bowl and add the garlic, mustard, green onions and parsley. Mix well. Add more mustard and salt and pepper to taste and set aside. (The mustart butter may be stored, covered in the refrigerator or rolled into a cylinder and frozen until needed.)
Trim the root ends of the sprouts and remove loose or discolored leaves. Cut the sprouts in half then crosswise into fine shreds. (Do not use a food processor, the leaves will be too fine.) Melt 1/2 cup of the mustard butter in a large skillet over medium heat. Saute the sprouts until tender, about 5 minutes. Lower the heat and stir in the caraway seeds, more mustard butter and salt and pepper to taste. Serve with lemon wedges.