Adjust rack to top position (top and middle positions for 4 servings) and preheat oven to 450 degrees. Place 2 TBSP butter (4 TBSP for 4) in a small bowl; set aside to soften. Wash and dry produce.

Trim and halve zucchini lengthwise; cut crosswise into ½-inch-thick half-moons.

In a separate small bowl, combine panko, Italian cheese blend, half the Italian Seasoning (you'll use the rest in the next step), a drizzle of olive oil (large drizzle for 4), salt, and pepper.

Pat chicken* dry with paper towels and season all over with remaining Italian Seasoning, salt, and pepper.

Place chicken in one oven-ready tray (for 4 servings, divide between two trays). Brush tops of chicken with sour cream. Mound with panko mixture, pressing to adhere (no need to coat the undersides!).

In remaining oven-ready tray, toss zucchini and tomatoes with a drizzle of olive oil, ½ tsp garlic powder (you'll use the rest in the next step), salt, and pepper. (For 4 servings, place zucchini in one of the remaining trays and tomatoes in the other; use a drizzle of olive oil, ½ tsp garlic powder, salt, and pepper for each tray.)

Place trays side by side on top rack (be sure your oven has preheated!); bake until chicken is cooked through and veggies are tender, 20-25 minutes. (For 4, bake chicken on top rack and veggies on middle rack, swapping rack positions halfway through.)

When chicken and veggies are almost done, to bowl with softened butter, add remaining garlic powder, salt, and pepper. Stir to combine.

Halve and toast ciabatta.

Spread cut sides with garlic butter. Cut each half on a diagonal.

Once veggies have finished roasting, add basil paste; stir to combine. (For 4 servings, combine roasted veggies with basil paste in one tray; alternatively, transfer veggies to a large bowl, then stir in basil paste.)

Divide chicken and veggies between plates in separate sections. Drizzle veggies with as much balsamic glaze as you like. Serve with garlic bread and chili flakes on the side.