Step 1: Melt the butter
In a large skillet or saucepan, melt 3 tablespoons of butter over medium heat.

Step 2: Add onions and cook until soft
Add the thinly sliced onion and cook for 6–8 minutes, stirring frequently, until softened and golden. This step builds the base flavor of the gravy.

Step 3: Add mushrooms and garlic
Stir in 8 oz of sliced mushrooms and 1 tablespoon of minced garlic. Cook for another 5–7 minutes, until the mushrooms are browned and have released their moisture.

Step 4: Add seasoning
Sprinkle in 1 teaspoon of Italian seasoning and season with the salt and pepper. Stir to evenly coat the vegetables.

Step 5: Add the flour
Sprinkle ½ cup of all-purpose flour over the mushroom and onion mixture. Stir constantly for 1–2 minutes to form a roux. This will thicken the gravy as it cooks.

Step 6: Pour in the beef broth
Slowly add 3 cups of beef broth while whisking or stirring vigorously to prevent lumps. Keep the heat at medium.

Step 7: Simmer to thicken
Bring the mixture to a gentle simmer. Let it cook for 5–7 minutes, stirring often, until the gravy thickens to your desired consistency.

Step 8: Adjust seasoning
Taste the gravy and adjust with additional salt or pepper if needed. Optional: stir in a splash of Worcestershire sauce or soy sauce for added richness.

Step 9: Serve hot
Serve the gravy immediately over your favorite dish, or keep warm on low heat until ready to use.