Grilled Venison Tenderloin

• 6 black peppercorns (whole)
• 2 garlic (cloves crushed)
• 2 bay leaves
• 1 onion (yellow chopped)
• 1/2 filets
• 950 gr venison tenderloin (cut)
• 60 ml wine vinegar (red)
• 60 ml water
• 60 ml rose wine
• 2 ml dry mustard