Beef Tenderloin with Marsala without greens tomatoes

4 tablespoons butter 2 tablespoons olive oil 14 ounces white button mushrooms , sliced (can use more) 2 -3 tablespoons shallots , finely chopped (or to taste)[...]

2 cups dry red wine 1 cup tawny port 2 cups beef broth 3 tablespoons butter 2 onions , chopped 1 tablespoon fresh thyme , chopped (or use 1 teaspoon dryed) 3[...]