Heat a large, heavy bottom pan over medium-high heat. Add in a 2 count of olive oil (approx 2 tbsp). When the oil shimmers, add in the onion. Add a pinch of salt, stir and cover. Cook for 10-12 minutes, stirring occasionally until browned and soft. Set aside in a large bowl.
In the same pan, add in 1 tablespoon olive oil. When it is shimmering, add in the diced zucchini and a pinch of salt. Cook for 6-7 minutes or until nicely golden brown and tender. Add to the large bowl.
Again in the same pan, add in the bacon fat... Add in the sweet potato, 2-3 pinches of salt and a couple cranks of pepper. Cover. Cook, stirring occasionally for 8-10 minutes. When golden and tender, remove from the pan and add to the bowl.
In the same pan, cook the sausage. Make sure to break up the sausage well while cooking so that it all gets cooked through. When it is completely cooked, remove and put on a plate covered with a couple paper towels. This will remove some of the grease. When it has a minute to rest, add the sausage to the other ingredients in the bowl.
Mix all the ingredients together, taste and adjust seasonings. Cover the bowl with foil and set aside.