Heat 1/2 tsp. olive oil in a medium sauté pan over medium-high heat.
Remove casing and drop large chunks of sausage into the pan, evenly distributed. Cook for 3-4 minutes, stirring occasionally, and turn halfway through. Remove sausage from pan and set aside. You can also use 8-10 oz. of un-cased italian sausage.
Add remaining olive oil to the pan. Add in the zucchini, mushrooms, onion, and garlic. Season with sea salt and pepper. Stir and cook for 5 minutes until vegetables are softened.
Return sausage to the pan and cook for an additional 1-2 minutes until sausage is cooked through.
Divide between 2 plates. Top with feta cheese and garnish with Italian parsley (optional).