Place the piece of filet in a shallow dish and rub with the olive oil, chopped rosemary and mashed garlic. Season with salt and pepper. Marinate overnight.
Combine breadcrumbs, parsley and green onions in the work bowl of a food processor. Pulse until mixture is finely chopped and breadcrumbs have turned
green. Add the andouille and pulse until finely ground. Place on a shallow pie pan and reserve.
Place garlic cloves in small saucepan. Cover with cold water and bring to a boil on top of the stove. Drain and repeat the process three more times. Return the garlic to the saucepan, cover with milk, add the sage and a pinch of salt. Simmer for 15 minutes until garlic is soft. Remove the sage and puree and on high until smooth. If necessary add a little more milk to thin to the consistency of heavy cream. Keep warm while cooking the filet.
Preheat oven to 425°F. Remove beef from the refrigerator and allow to come to room temperature. Heat a large skillet over high heat. Add the vegetable ol to the pan and sear the filets to the pan. Add the butter and rosemary sprigs to the pan. Brown on the first side and turn, basting with the butter and oil. Cook for a couple minutes to brown the second side. Transfer to a sheet pan with a rack. Brush one side with the Dijon mustard and top with the breadcrumb mixture. Return to the oven and cook for another 5-7 minutes for medium rare or desired doneness. Remove from the oven and serve with a spoonful of the garlic sauce.
Enjoy with a glass of Cakebread Cellars Benchland Select.