Heat oil over medium heat in a large pan. Add onions, garlic, mushrooms, bell pepper, celery and carrots. Stir and cook for a few minutes. Add salt, thyme, paprika, red chili flakes, then stir to combine. Cook for about 10 minutes, until vegetables have softened. Add black eyed peas and cook for another 5 minutes. Remove from heat and set aside.
To make the gravy, heat oil or vegan butter over low-medium heat. Whisk in flour. Cook for a couple of minutes while continuing to whisk. Slowly add in the broth, while whisking, to ensure there are no clumps of flour. Whisk in nutritional yeast, tamari, onion and garlic powders, and white pepper. Continue to cook, whisking continuously, until mixture is thick and velvety. Taste and adjust seasonings, add more broth to thin if necessary. You’re finished when the mixture is glossy and coats the back of a spoon. Scoop black eyed pea mixture into the pan with the gravy and heat for a few minutes more so that the flavors mingle.
To serve, warm the biscuits in the oven, if cold, then slice in half. Arrange on a plate and ladle black eyed peas and gravy over both sides. Sprinkle with scallions and enjoy.