Cook sausage patties in a black cast iron skillet till done, obviously. Then remove the sausage and put it on some paper towels to blot up some of the grease.
Drain grease from pan leaving only enough to coat the bottom (about 2 tablespoons), add a handful of flour (3 tablespoons will do) to the grease and cook it, stirring ALL the time, till it turns brown.
Add the milk to the browned flour and stir till all the lumps are gone and it's thick. Add the drained Ro-Tel tomatoes and stir till it's the consistency that you like. (add more milk if it's too thick).
Crumble up the sausage and add back to the gravy then spoon it over hot biscuits.
Then turn around and slap the person next to you on account of it's so good you just have to slap somebody!