Bring a large cast iron skillet to medium-high heat. Add oil; swirl to coat the pan. Add onion and garlic. Move around pan until onion softens and garlic is fragrant; about 1-2 minutes.

Add sausage. Break up with spatula and move around pan until fully cooked, approx. 5-7 minutes. Drain off any excess liquid, if any. Add dried oregano and dried basil. Stir to combine. 

Add orzo, broth, salt, and pepper. Stir to combine. Bring to a gentle simmer and let orzo cook, uncovered, approx. 8-12 minutes or until orzo is cooked al dente. Stir the orzo occasionally and add additional splashes of chicken broth, as needed, if the pan starts to feel dry before the orzo is done - this will help prevent the orzo from sticking to the bottom of the pan. 

Meanwhile, as the orzo cooks sauté the zucchini. Bring a large sauté pan to medium heat. Add the butter and swirl to coat the pan. Add zucchini quarters and toss gently in the butter. Season with kosher salt and ground black pepper. Let cook until zucchini soft, but firm - approx. 3 minutes. Remove from heat. 

Once orzo is fully cooked remove from heat. Add the zucchini, grated parmesan cheese, grated mozzarella cheese and a tiny bit of lemon zest for some acidity. Stir gently to combine as the cheese melts (if you don't remove the skillet from the heat the cheese will overheat).

Taste and add additional salt, as needed - this will depend a lot on how salted or seasoned your Italian sausage was so it will differ person to person - taste and add more if you need to.

Serve with some marinara sauce on top (as much or as little as you want), shredded mozzarella and fresh basil leaves.