Step 1

Melt the butter in a large skillet over medium high heat.

Step 2

Add the sliced onions and cook for about 30 minutes until beginning to caramelize.

Step 3

Add the red wine and thyme, bring to a boil, then reduce the heat to a simmer and cook for 10 minutes.

Step 4

Add the broth, Worcestershire sauce, mustard, salt, and pepper, bring to a boil, then reduce the heat to a low simmer and cook for 20 minutes.

Step 5

Remove the thyme stems.

Step 6

In a small bowl whisk together the cornstarch and 2 TBSP water. Slowly add the cornstarch mixture to the gravy whisking to combine. Boil just until thickened. Season with additional salt and pepper, to taste.

Step 7

Enjoy.