Add oil to a large skillet and heat over medium heat.

When oil is hot and shimmering, carefully add mushrooms, onions, peppers and celery. Sauté until vegetables are soft and mushrooms have given up their liquid.

Add black pepper, Worcestershire Sauce and chicken base. Turn off heat.

Drizzle in flour and mix well with a whisk, making sure their are no lumps.

Turn heat back on and bring to a simmer, stirring occasionally to make sure gravy does not stick to the bottom and/or burn, for 15 minutes. Adjust heat as needed.

Remove from heat and serve with Disney's House of Blues Cajun Meatloaf.