Lamb Steaks With Vermouth And Rosemary

• 6 lamb steaks from the boned
• 1 clove garlic
• 1 onion
• 120 gr dry vermouth
• 80 gr mushrooms
• 45 gr butter
• 18 gr shallot (chopped)
• 5 gr parsley (minced fresh)
• 3 gr salt
• 1 gr pepper