In a large skillet or saucepan, melt unsalted butter over medium heat.

Add thinly sliced onions to the skillet and cook, stirring occasionally, until the onions are caramelized and golden brown, about 20-25 minutes.

Sprinkle all-purpose flour over the caramelized onions in the skillet and stir to coat evenly.

Cook the onions and flour mixture for an additional 1-2 minutes, stirring constantly, to cook off the raw flour taste.

Gradually pour beef broth into the skillet, stirring constantly to prevent lumps from forming.

Stir in Worcestershire sauce and dried thyme, and season with salt and pepper to taste.

Bring the gravy to a simmer, then reduce the heat to low. Cook, stirring occasionally, for 10-15 minutes, or until the gravy has thickened to your desired consistency.

Taste the gravy and adjust seasoning if necessary.

Once the gravy is cooked to your liking, remove the skillet from the heat.

Serve the Onion Gravy hot over mashed potatoes, roasted meats, or your favorite comfort foods. Enjoy!