Make the flour mixture - In a large food processor or a large bowl, measure out 3 cups of flour, (use a spoon to fill the measuring cups) 2 tbsp of baking powder, and 1 tsp salt, into a bowl. Give it all a stir.
Add 1/2 cup of room temperature coconut oil, shortening, or (cold butter) to a food processor and plus it a few times until the mixture looks like sand (or mix in a large mixing bowl with a pastry cutter or large fork until well combined).
Once the dry ingredients and fat are mixed well, slowly add the plant-based milk and fold the mixture until a soft dough is formed. (You may need slightly more or less milk depending on how you measured and what type of flour you are using). Mix just until you can no longer see dry flour and you have a shaggy dough.
Drop large spoonfuls of the dough onto an ungreased baking sheet. (There is no need to grease the pan or line it with parchment paper, these biscuits don't stick to the pan.)
Bake at 450° F (232° C) for 12 minutes.
Make the gravy
Wash and dice a green pepper into small pieces and set aside.
Add 1 tbsp of cooking oil to a large skillet and fry your choice of vegan sausage over medium heat until cooked through and slightly browned. (If using sausage links break them up into small pieces with a wooden spatula while they cook.)
Add 2 tablespoons of vegan butter and the diced bell pepper and cook for another minute.
Sprinkle the sausage and peppers with 1/4 cup of all-purpose flour and stir until coated.
Slowly add 2 1/2 cups of oat milk 1/2 cup at a time stirring well between each scoop until the gravy is thick and bubbly.
Season with garlic powder, salt, pepper, and sage to taste.
Notes
Be sure to spoon-measure your flour. This means spooning the flour into the measuring cup and using the back of a knife to gently level the flour. If you scoop the flour out with a measuring cup, you will pack it down and have more flour than you need which will result in dry biscuits.
Don't over-mix the dough. As soon as you can no longer see dry flour stop mixing.
Add the liquid to the roux slowly being sure to stir well between each scoop.
Make sure to stir constantly during the thickening process.