Remove the sausage from casing and fry in cast iron or heavy pot (you can either crumble, or make mini-patties). When browned and cooked through, put in 170 degree oven to keep warm.
Add 1 tsp canola oil to rendered sausage fat and heat to medium. Saute onions until golden (not brown). Put potatoes in and quickly incorporate onions and potatoes together. Let sit until bottom is nicely browned. Flip to brown other side. When potatoes are golden brown and tender, remove them to a platter. Mix Ranch dressing with onions and potato mixture. Place sausage over top of potatoes. (NOTE: if you are frying eggs up, put potatoes and sausage back in 170 oven until eggs are done) Top with German mustard (if you're not lucky enough to have real German mustard where you are, Gulden's is an acceptable substitute :) )
This is a great main brunch dish or a hearty dinner served with red cabbage :)