Carmelized onions (see below)
Sauteed mushrooms
To marinate meat, whisk together garlic, onion, salt, pepper, olive oil, red wine vinegar and mustard in a bowl. Place meat in a gallon-size reclosable bag. Pour the marinade over the meat, making sure that the entire surface is coated. Refrigerate for at least one hour or up to 24 hours before preparing.
To cook, either grill or broil the meat until a meat thermometer registers 150 degrees (medium). Allow meat to rest for 5-10 minutes before slicing. You may not want to cook this cut of meat past medium as it may become tough.
Caramelized onions can be made by sauteing 1/2 cup sliced onion in 1 tablespoon of butter until onions are translucent. Sprinkle 2 teaspoons of brown sugar over the translucent onions, stirring for about 1 minute until the sugar melts and the onions are coated.
Saute 8 ounces of sliced mushrooms in 2 tablespoons olive oil (or use half butter and half olive oil).