Add 1 of the TBSPs of Earth Balance to the sauté pan, heat at medium and add onions, garlic, and mushrooms. Stir occasionally at medium heat while you make the roux/slurry in the sauce pot.
Add the other TBSP of Earth balance to the sauce pot and melt over medium heat. Sprinkle flour over the melted Earth Balance and whisk together. Then add broth and whisk until clumps are gone. Next, add unfortified nutritional yeast, soy sauce, and black pepper, whisking until combined. Reduce heat for the sauce pot from medium to low heat.
Turn sauté pan heat to up to medium-high to finish sautéing until mushrooms are a deeper brown color and onions are translucent.
Add mushrooms and onions from the sauté pan to the sauce pot. Let simmer, whisking occasionally until gravy reaches desired thickness. Taste and season with additional salt, soy sauce, pepper, or nutritional yeast. Serve and enjoy or store to enjoy later.