You need to make the stock to start with. You can do this up to a week ahead and just keep it refrigerated. You'll have enough stock to make a double batch of gravy if you need it. If you don't, just freeze the leftovers for later use.
Roasted vegetable stock (7 - 8 cups, original recipe here)
1/2 lb portabella mushrooms, cut into 1" pieces:: Preheat oven to 425 F.
1 lb shallots, left unpeeled, quartered
1 lb carrots, cut into 2" pieces
2 red bell peppers, cut into 1" pieces
6 fresh flat-leaf parsley sprigs (including stems)
5 fresh thyme sprigs
4 garlic cloves, coarsely chopped
2 tablespoons olive oil
1 cup dry white wine
1 cup canned crushed tomatoes
2 quarts water
:: Toss together all vegetables and herbs along with the olive oil. I use a giant bowl and a spatula to coat everything evenly. Dump everything onto a roasting pan (I find that two half sheet pans give you the best distribution but you can just use one) and roast for 30 - 40 minutes, until everything is tender and golden. Turn occasionally during the cooking process and if you're using two pans, switch positions half way through.
:: Transfer everything to a 6 quart stockpot. Set the roasting pan across two burners. Add wine and deglaze the pan by boiling over medium heat briefly, stirring and scraping up brown bits. Since I use two pans I deglaze each with half a cup of the wine. Pour the wine off into the stockpot and add the tomatoes and the water. Bring to a boil, then reduce heat and simmer, uncovered, stirring occasionally, 45 minutes. Pour through a large fine sieve into a large bowl, pressing on and discarding solids. The original recipe has you season with salt and pepper but I prefer to leave it unsalted and just salt the gravy. Refrigerate and skim off fat if you have any, which I rarely do.
- Stock keeps, covered and chilled, one week, or frozen three months. You'll get 7 - 8 cups out of this. If you're making a single batch of gravy, pour the leftover stock into large ziploc bags and freeze on a cookie sheet so they're flat and easy to store. I also use some of the stock to moisten the dressing, so I keep about a cup out.
Best vegetarian gravy (makes 3.5 cups, original recipe here)
1/2 stick (1/4 cup) unsalted butter:: If your stock has been chilled, heat it in a saucepan on the back burner and leave it at a low simmer.
1/3 cup all purpose flour
3 cups roasted vegetable stock, heated
1/4 cup heavy cream
1/2 teaspoon salt
1/4 teaspoon pepper
:: Melt butter in a saucepan over moderate heat, then whisk in flour and cook roux, whisking constantly, until a nutty brown color, about 5 - 10 minutes. The darker your roux, the better your flavor, so wait until it smells toasted but don't let it tip over into burned. (The picture above the recipe was about halfway through the process)
:: Add hot stock in a fast stream, whisking constantly to prevent lumps. This will produce a big gust of hot steam at first, so be careful! I usually whisk in half, whisk for a bit to ensure that it's nice and smooth and then add the rest at a slower pace to incorporate it.
:: Bring to a boil, then reduce heat and simmer, whisking frequently, until thickened to desired consistency, about 6 - 8 minutes. Turn off the heat, stir in the cream, salt and pepper.