Prep the zucchini. Preheat your oven to 400°F (200°C). Trim the ends of the zucchini and slice them lengthwise. Use a spoon to scoop out the seeds and some flesh, creating “boats.” Chop the scooped flesh and set it aside.

Sweat the zucchini shells. Sprinkle the inside of each zucchini boat with a little salt and set them cut side down on a paper towel for 10 minutes. This pulls out excess moisture so the boats bake more evenly.

Sauté the aromatics. In a large skillet, heat 2 tablespoons olive oil over medium heat. Add the onion and cook until soft and translucent, about 5 minutes. Stir in the garlic and cook 30 seconds, until fragrant.

Build the filling. Add the chopped zucchini flesh and cherry tomatoes to the skillet. Season with salt, pepper, oregano, and red pepper flakes if using. Cook, stirring, until most of the moisture cooks off, 5–7 minutes.

Finish the mixture. Remove from heat. Stir in breadcrumbs, Parmesan, parsley, basil, and lemon zest. Taste and adjust seasoning. Fold in half of the mozzarella.

Fill the boats. Pat the zucchini shells dry. Arrange them in a baking dish and spoon the filling evenly into each boat, mounding it slightly. Top with the remaining mozzarella and a light drizzle of olive oil.

Add moisture for baking. Pour the broth into the bottom of the baking dish to help steam the zucchini as it bakes. This keeps the boats tender without drying out.

Bake. Bake uncovered for 18–22 minutes, until the zucchini is tender and the cheese is melted and lightly golden. If you want extra color, broil for 1–2 minutes at the end.

Rest and garnish. Let the stuffed zucchini rest for 5 minutes so the filling sets. Garnish with extra basil and a pinch of black pepper. Serve warm.