Prep the oven and pan: Heat oven to 400°F (200°C). Lightly oil a large baking dish.

Hollow the zucchini: Slice each zucchini lengthwise. Use a spoon to scoop out the center, leaving about 1/4 inch of flesh to form boats. Chop half of the scooped zucchini and save it for the filling. Season boats with a pinch of salt and pepper.

Pre-bake the boats: Place zucchini cut-side up in the baking dish. Bake for 10 minutes to soften slightly. This helps prevent sogginess later.

Sauté aromatics: While boats bake, heat olive oil in a large skillet over medium. Add onion and bell pepper. Cook 3–4 minutes until softened. Add garlic and the chopped zucchini flesh. Cook 1–2 minutes more.

Brown the meat: Add ground meat to the skillet. Cook, breaking it up, until no longer pink. Drain excess fat if needed.

Season and simmer: Stir in taco seasoning, tomato paste or salsa, diced tomatoes, black beans, and corn. Add a splash of broth or water to loosen. Simmer 3–5 minutes until thick and saucy. Taste and adjust salt, pepper, and seasoning.

Fill the boats: Spoon the taco mixture into each pre-baked zucchini boat, packing it in firmly. You should have a generous mound on top.

Add cheese: Sprinkle shredded cheese evenly over the boats.

Bake to finish: Return to the oven for 10–12 minutes, until zucchini is tender and cheese is melted. For a golden top, switch to broil for 1–2 minutes at the end, watching closely.

Garnish and serve: Top with chopped cilantro or green onions. Add optional dollops of Greek yogurt, avocado slices, and a squeeze of lime. Serve hot.