To make a filet mignon marinade, mix together 1/2 cup extra virgin olive oil, 1 tablespoon minced garlic, 1 tablespoon chopped fresh basil, 1 tablespoon chopped fresh parsley, 1 teaspoon blackening seasoning and salt and pepper to taste. Place in a bag at room temperature with 2 pounds filet mignon steaks or tenderloin and allow them to sit for 30 minutes. Grill or roast steaks that use this marinade, and top them with mushrooms if you choose.
For another filet mignon marinade, combine in a shallow bowl: 1/2 cup extra virgin olive oil, 3/4 teaspoon seasoning salt, 3/4 teaspoon lemon-pepper seasoning, 3/4 teaspoon dried oregano and 1/2 teaspoon garlic powder. Add six beef tenderloin steaks to the bowl, cover and allow to marinate for three hours in the refrigerator, turning occasionally to marinate on both sides. With this marinade, the steaks should be grilled.
For a spicier marinade, whisk together 1/2 cup prepared non-creamy horseradish, 1/4 cup prepared Creole mustard, 10 to 12 peeled, finely chopped garlic cloves, 2 tablespoons olive oil and 2 tablespoons cracked black pepper. Spread the marinade generously over one 2-pound beef filet mignon, and cover and marinate in the refrigerator for one to two hours. This marinade is appropriate for grilling or roasting.