Preheat your oven to 375°F (190°C) to ensure even baking.

Cut the zucchinis in half lengthwise and scoop out the seeds to create a boat shape. Set aside the scooped-out flesh for later.

In a skillet over medium heat, add a drizzle of olive oil. Sauté the onions and garlic until fragrant, about 2-3 minutes.

Add the ground beef, cooking until browned and crumbled. Drain any excess fat.

Stir in the reserved zucchini flesh, marinara sauce, Italian seasoning, salt, and pepper. Cook for another 5 minutes until everything is well combined and heated through.

Spoon the beef mixture into the hollowed zucchinis, packing them tightly.

Top with shredded cheese.

Place the filled zucchinis on a baking sheet and bake for about 20 minutes, or until the zucchini is tender and the cheese is bubbly and golden.

Garnish with fresh basil before serving.