Preheat broiler to high or oven to 500 degrees. Wash and dry all produce. Trim ends from zucchini, then grate using large holes of a grater. Trim, then thinly slice scallions, separating whites from greens.

Heat 1 TBSP oil in a large pan over medium-high heat (use an ovenproof pan if you have one). Add sausage and 1 TBSP Italian seasoning (we’ll use the rest later). Cook, break up meat into pieces, until browned and cooked through, 3-5 minutes. Turn off heat; transfer to a large paper-towel-lined bowl.

Add zucchini, scallion whites, and another 1 TBSP oil to same pan over medium-high heat. Cook, tossing, until tender and zucchini has shrunk by about a third, about 5 minutes. Season with salt and pepper. Transfer to bowl with sausage. Wipe out pan.

Melt 2 TBSP butter in same pan over medium-high heat, then add orzo and toss to coat. Toast, tossing often, until golden, 2-3 minutes. Stir in 3 cups water, stock concentrates, tomatoes, and remaining Italian Seasoning. Bring to a boil and cook, stirring occasionally, until orzo is al dente, about 12 minutes.

Drain any excess liquid from sausage and zucchini, then stir both into orzo in pan. Add another 2 TBSP butter and stir to melt. Season with salt and pepper. Remove pan from heat. (TIP: Transfer contents of pan to a baking dish at this point if your pan is not ovenproof.) Sprinkle mozzarella and panko evenly over pan or dish.

Place pan or dish under broiler— surface should be about 3 inches from heat. Broil until panko is golden brown and mozzarella melts, 2-3 minutes. (TIP: Keep an eye out for any burning.) Remove from broiler, then scatter with scallion greens and divide between plates.