Step 1

Melt the butter (or bacon grease, lard or beef drippings - any of these will yield the most flavor) in a pan over medium-high heat and fry the onions until beginning to brown.  Add the garlic and cook another minute.

Step 2

Add the mushrooms and cook 5-7 minutes or until golden and the liquid from the mushrooms has evaporated.

Step 3

Add the butter and melt.  Add the flour, stir to combine and cook for about 2 minutes, stirring continually.

Step 4

Add the beef broth, vinegar, thyme, sugar, salt and pepper.  Whisk continually until the gravy is thickened.  Cover and simmer on low, stirring occasionally, for 5-10 minutes.  Add salt and pepper to taste.  If you prefer the gravy thinner add a little more water (or heavy cream if using)