Created by breezermom on December 26, 2015
Step 1: Combine the first 7 ingredients in a small bowl; stir well.
Step 2: Place tenderloin in a large shallow dish or large zip-lock bag. Pour marinade mixture over the tenderloin. Cover and marinate in the refrigerator for 8 hours, turning occasionally.
Step 3: Remove the tenderloin from the marinade, reserving marinade. Place the marinade in a small saucepan. Bring to a boil; reduce heat and simmer 3 minutes. Set aside.
Step 4: Place tenderloin on a rack in a shallow roasting pan; insert meat thermometer, making sure it does not touch fat. Bake at 425 degrees for 45 to 55 minutes or until the thermometer registers 140 degrees (rare), 150 degrees (medium-rare), or 160 degrees (medium). You really shouldn't cook it past medium-rare for the best taste and tenderness. Baste with the marinade occasionally. Let the tenderloin stand for 10 minutes before serving.
Step 5: Saute mushrooms in 1 tablespoon melted butter in a skillet until tender; set aside, and keep warm.
Step 6: Place the remaining marinade in a small saucepan; add water and 2 tablespoons butter. Bring to a boil; reduce heat, and simmer 3 minutes.
Step 7: Slice tenderloin; spoon sauce over tenderloin. Top with sauteed mushrooms.