To make a good wine sauce, sauté aromatic vegetables such as onions, garlic and celery in olive oil. Once the aromatics turn golden, add wine to pan. Simmer the sauce until the volume is reduced by half before adding flour to thicken the sauce and a little butter for richness.
Start by heating the pan on medium-high. When hot, add 1 tablespoon of olive oil and 1/4 to 1/3 cup of diced onions or shallots. Once the onions begin softening, add 1 to 2 cloves of minced garlic. When the vegetables become browned, pour 1/2 to 3/4 cup of white wine into the pan, scraping the bottom to release any cooked-on, flavorful bits.
Simmer the sauce until it's reduced by half before adding another tablespoon of oil or butter. Whisk in 1 to 2 tablespoons of flour, and continue simmering the sauce until it thickens. You can also add up to 1/4 cup of fresh herbs for flavor, of 1/2 to 1 cup of broth, milk or cream to add volume to the sauce. Season the white wine sauce with salt and pepper to taste.
For a lighter version, sauté the aromatic vegetables in a pan coated with cooking spray. Add 1/2 cup of chicken broth, 1/4 cup of dry white wine and 2 tablespoons of white wine vinegar. Simmer the sauce for approximately five minutes. Remove it from the heat, and stir in 2 tablespoons of butter.