Heat 1/4 cup of butter in a pan. Add the chopped onion and garlic. Cook over medium-low heat until caramelized.
Scoop out the caramelized onion with a sieve and press to allow the butter to drip back into the pan. Transfer the cooked onion to the blender. Pour in a cup of broth. Process until the onion bits are liquefied.
Reheat the remaining butter in the pan. Add the flour all at once. Mix until there are no lumps. Cook over medium heat to make a brown roux.
Pour in the broth with the pureed caramelized onion. Pour in a thin stream, stirring with the other hand as you pour. Let the mixture simmer until thickened. If the gravy is too thick, add the rest of the broth little by little until you get the consistency that you like.
Off the heat, season with salt and pepper. Stir in the remaining two tablespoonfuls of butter until melted.
Velvety Onion Gravy printed from https://casaveneracion.com/the-ultimate-guide-to-mashed-potatoes-and-gravy/ for personal use only. Not for republication nor distribution.