Preheat oven to 450 degrees F (232 C) and prepare biscuits. Add to baking sheet. Place in the oven once you get to step 6 (when adding the walnuts to the gravy).
Add butter or olive oil to a cast iron skillet or large saucepan over medium heat. Then add garlic, onion, mushrooms and season with a pinch each salt and pepper. Cook for 3-4 minutes or until the onions are translucent.
Add flour and whisk to coat. Cook for 1 minute.
Then slowly whisk in broth and almond milk, starting with 1/2 cup almond milk and building up. Season again with a pinch each salt and pepper.
Cook until thickened, stirring frequently, over low heat. Taste and adjust seasonings as needed. I go heavy on the pepper out of preference.
Add walnuts and stir to combine. Keep on low until you’re ready to serve, adding more almond milk as needed if it gets too thick. (Bake biscuits for 10-15 minutes.)
To serve, split biscuits and top with gravy. Store leftovers separately - store gravy covered in the fridge for up to 3-4 days, and store biscuits (once completely cooled) at room temperature in a tupperwear or plastic bag. Reheat in a 350-degree F (176 C) oven to keep flakiness intact.