1. Vegetable Puree: You can use pureed vegetables to thicken your sauce. Cook and blend vegetables like potatoes, cauliflower, or carrots until they are smooth, then mix this puree into your sauce to achieve the desired thickness. This method works well for creamy and vegetable-based sauces.
2. Cornstarch Slurry: Instead of flour, you can use a cornstarch slurry to thicken your sauce. Mix cornstarch with a small amount of cold water to create a smooth paste. Then, gradually stir this slurry into your sauce while it’s simmering. Keep in mind that cornstarch can make the sauce appear glossy, so use it sparingly.
3. Reduction: Reducing a sauce by simmering it for an extended period can naturally thicken it. The liquid in the sauce will evaporate, leaving behind a more concentrated and thicker sauce. This method works best for sauces with strong flavors like tomato or wine-based sauces.

These alternatives can help you achieve a thick and flavorful sauce without using traditional flour-based roux.

Starch: You can use potato or corn starch, and there won’t be much difference in taste. The more starch you add, the thicker the sauce will become. However, you should not simply sprinkle starch into boiling gravy as it may form lumps. Instead, mix the starch with water and pour the resulting slurry into the sauce. Add the diluted starch slowly while vigorously stirring the gravy with a whisk or spoon. The sauce will start to thicken quickly.

Mustard: We’re not talking about prepared mustard seasoning here, but mustard powder. It can not only thicken the sauce but also add a piquant flavor and spiciness. Mix one or two teaspoons of mustard powder into a small amount of cooled sauce, and then pour this mixture back into the gravy.

Sour Cream or Butter: Adding sour cream will make the sauce creamier and give it a rich taste. It’s best to use full-fat sour cream, preferably homemade. Add it at the end of cooking and do not bring the sauce to a boil after adding sour cream. In other words, add it, stir, and immediately remove it from the heat.

For butter, it’s better to add it to the sauce after removing it from the heat but while it’s still very hot. Cut the butter into small pieces, add it to the sauce, and stir vigorously.

Vegetables: This is probably the healthiest way to thicken a sauce. Sauté a small amount of oil, onions, and carrots until they become soft. This forms the base to which you can add other vegetables like bell peppers or even mushrooms. Cook them until they become tender and excess liquid evaporates. Then, using a blender or a fine sieve, turn the vegetables into a puree and add it to the sauce. This addition not only thickens the gravy but also enhances its flavor.