To prepare filling: Heat 2 teaspoons oil in a Dutch oven over medium heat. Add onion and bell pepper; cook, stirring often, until softened, about 3 minutes. Add garlic and cook, stirring, for 30 seconds. Stir in zucchini; cook, stirring often, for 3 minutes. Stir in chili powder, cumin, cinnamon and 1 teaspoon salt; cook for 20 seconds. Pour in tomatoes and their juice; bring to a simmer. Remove from the heat. Stir in shrimp and cilantro. Pour into a 9-by-13-inch baking pan.

Preheat oven to 350 degrees F.

To prepare cornbread topping: Whisk cornmeal, flour, baking powder and 1/2 teaspoon salt in a large bowl. Whisk milk, 1/4 cup oil, egg and honey in a medium bowl until smooth. Add the wet ingredients to the dry ingredients and stir just until moistened. Drop by heaping tablespoons over the shrimp mixture.

Bake the casserole, uncovered, until the top is browned and the filling is bubbling, 40 to 45 minutes. Let stand for 10 minutes before serving.

Ingredient note: Shrimp is usually sold by the number needed to make one pound. For example, "21-25 count" means there will be 21 to 25 shrimp in a pound. Size names, such as "large" or "extra large," are not standardized, so to be sure you're getting the size you want, order by the count (or number) per pound. Both wild-caught and farm-raised shrimp can damage the surrounding ecosystems when not managed properly. Fortunately, it is possible to buy shrimp that have been raised or caught with sound environmental practices. Look for fresh or frozen shrimp certified by an independent agency, such as Wild American Shrimp or Marine Stewardship Council. If you can't find certified shrimp, choose wild-caught shrimp from North America--it's more likely to be sustainably caught.

MAKE AHEAD TIP: Bake, let cool for 1 hour, cover with parchment paper then foil and refrigerate for up to 3 days. Reheat, covered, in a preheated 350 degrees F oven for 1 hour.