Related: Fork-and-Knife Roasted Vegetables
- Heat butter and oil in large saucepan over medium heat. Add onions, celery, and mushrooms, and season with salt, if desired. Cover, reduce heat to medium-low, and cook 10 minutes, or until vegetables begin to soften. Uncover, add garlic, and cook 30 minutes, or until vegetables are very soft and most of liquid has evaporated, stirring occasionally.
- Stir in flour, and cook 3 to 4 minutes, or until flour begins to brown. Stir in wine (if using), and cook 1 to 2 minutes. Add 5 cups water, thyme, marjoram, and rosemary. Cover, reduce heat to medium-low, and simmer 40 minutes, stirring occasionally.
- Strain gravy through a fine-mesh sieve. Rewarm, if necessary.