Cut up the sausage and chop all of the vegetables.
Heat the olive oil & butter in a large skillet over medium heat for one minute. Swirl to coat the pan, add the kielbasa and onion, and saute for 3-4 minutes, stirring occasionally.
Stir in the zucchini, mushrooms, tomatoes, garlic, and spices. Continue to cook everything over medium heat for another 6 minutes, stirring occasionally.
After 6 minutes, stir the sausage & veggies, cover the skillet, and continue to cook over medium heat for another 13 minutes or until the zucchini is crisp-tender. Check and stir the skillet occasionally.
Sprinkle the shredded Parmesan across the entire skillet, then stir it in to melt. Continue sauteing uncovered for another two minutes, then taste and add more salt if necessary.
Optional: Serve the sausage & veggies garnished with chopped fresh parsley and/or additional Parmesan, if desired.
Notes
The skillet will be very full when you add in the zucchini and other veggies, but they’ll cook down fairly quickly, so no worries.