A thick and velvety onion sauce. It goes well with meat, fish, and dumplings

This long-simmered dark onion sauce with an exceptionally deep flavor and an impressive aroma will elevate your kitchen to a higher level. The list of ingredients is kept to a minimum, and the sauce making itself is incredibly simple. Try it once and you'll be hooked.

Caramelized onions and aromatic broth form the base of this dark vegetable sauce. These ingredients bring out a deep flavor and boldness. So prepared, it will play a star role when served with dumplings, and will perform well as an accompaniment to fish or meats served either hot or cold.

Slow cooking will extract the natural sweetness from the onion, which will beautifully blend with the light saltiness of the broth. The success is also due to a modest addition of spices: it's salt, pepper, and thyme (preferably fresh). Sage and rosemary will also work. However, remember that in this case, less is more.

You don't need flour or cream to thicken the sauce. A bit of patience and reduction is enough. It's a simple and effective, but time-consuming way to give the sauce thickness. You just need to cook the liquid on high heat until the excess water evaporates from it. Remember that the sauce should be stirred constantly so it doesn't stick or burn.

Ingredient:

• 5 medium-sized onions,
• 1 teaspoon of Dijon mustard,
• 1 teaspoon of apple cider vinegar,
• 2 cups of broth: vegetable, chicken, or beef,
• 1 sprig of fresh thyme or 1 teaspoon of dried,
• 4 tablespoons of butter,
• salt and pepper.

Preparation:

1. Heat 3 tablespoons of butter on a large skillet and sauté the onion sliced into feathers in it.
2. Add a pinch of salt and cook everything over low heat, often stirring for approximately 25 – 30 minutes. The onions should turn golden.
3. Add apple vinegar to the onions, sauté for a while. After a few minutes, add broth, thyme, and mustard.
4. Bring the sauce to a boil, after this reduce the burner power and cook everything without a lid until the sauce thickens. Remember to stir the sauce from time to time.
5. Season the sauce with salt and pepper. You may serve it with pieces of onion or blend everything smoothly.
6. If you want to serve a smooth sauce, remove the sprig of thyme earlier, blend everything and in the end, add a tablespoon of butter.