I wouldn’t double this recipe in an 11 x 13-inch pan. With that much chicken and zucchini in one dish, I’d be concerned about overcrowding and excess liquid, which could leave the casserole watery and affect how evenly the chicken cooks. For 8 people, I would make two separate batches in two 11 x 7-inch baking dishes. You can bake them at the same time, rotating the pans partway through if needed. That will give you a result much closer to the original recipe.

Yay, those are great additions.

You can use cooked chicken, just treat it differently. Since it’s already done, you don’t need the full bake time to cook it through. Mix everything together without the chicken first and bake it covered for about 15 to 20 minutes to get the vegetables going. Then stir in the shredded or cubed rotisserie chicken, add the cheese, and finish baking uncovered until everything is hot and the top is melted and golden.

This is a very old piece of Emile Henry stoneware collection. I could not find it on their website. But lots of their stoneware pieces are rated up to 520°F (270°C) and are broiler-safe, provided the dish is a safe distance from the heating element (typically at least 6 inches). Always check the specific product instructions. Le Creuset has a lot of broiler-safe pieces too, you just have to look at product specifications. Glad you enjoyed the zucchini and chicken dinner.

So happy to hear this!