We always have had people with different eating habits and preferences. I started making an alternative choice in gravies a few years ago, as we had quite few vegetarians as regular guests. I am lucky to come from a family that cooks instinctively, and to have lived in Berkeley long enough to hone my vegetarian and vegan cooking skills. I never really make it the same each time, I just whip it together. The common denominator for me is to have a good vegetable stock on hand. I usually buy a packaged organic vegetable stock and go from there. My daughter Jacki is a vegetarian, so I am making some this year. BUT Jacki can not stand mushrooms, which would normally be my first choice for gravy.
So this year I am making a green onion/garlic gravy, and it goes like this:
Start with about 4 Tbl. olive oil and heat in a skillet. Chop about 5 or 6 green onions, including a good portion of the green stems, and crush or mince two cloves of garlic. (Last year I did a combination of onion, leek and green onion. You could add mushrooms and other vegetables here, just add a little more oil so you have enough to mix with the flour).
Saute the garlic and onion until its starting to soften. Sprinkle in 2 Tbl. of flour and stir to incorporate it with the remaining olive oil. Add coarse ground black pepper, maybe a tsp. Leave the salt until after you add the broth and get a chance to taste it. Let the flour and oil bubble a little before adding a splash of the broth. You could also add a splash of white wine here as well. Once you get a good smooth roux add the remaining broth. You will add about 1 cup total. Simmer until it thickens.
Adjust the salt and seasonings, I added a little salt and some thyme, and added in about 2 Tbl. worth of finely grated carrot and let it bubble. Then, to add to the creaminess, I added one pat of butter and a Tbl. of sour cream. The thyme worked well to give it some richness and the butter and sour cream mellowed out some of the bitterness that comes from a rich vegetable broth.
Once you get the hang of sauteeing vegetables of your choice, adding some flour to your oil/fat/butter, and adding liquid (broth, wine, water, milk.cream), seasoning to taste, you can make a gravy out of almost anything.