Preheat the oven to 375°F. Grease a 9x13-inch baking dish. Cook the macaroni noodles according to package directions. While the noodles are cooking, continue making the casserole.

Add the ground beef to a large skillet and cook on medium heat until browned, breaking it up with a spatula as it cooks.

Add the chopped onion and sauté until translucent, about 2-3 minutes.

Add the minced garlic and sauté for an additional 30 seconds until fragrant.

Stir in the diced zucchinis and cook for 3-4 minutes until they start to soften.

Add the dried oregano, dried basil, red pepper flakes, salt, and black pepper to the skillet. Mix well to combine all the flavors.

Pour in the marinara sauce and let the mixture simmer for about 5 minutes, allowing the flavors to meld together.

Add the cooked macaroni to the skillet and gently mix everything until the macaroni is evenly coated with the sauce and meat mixture.

Gradually stir in the heavy cream to the macaroni mixture. This will add a creamy and rich element to the dish.

In a separate bowl, combine the shredded mozzarella, cheddar, and Parmesan cheeses.

Transfer half of the macaroni mixture to the greased baking dish. Sprinkle half of the cheese mixture over it.

Layer the remaining macaroni mixture on top and finish with the rest of the cheese.

Cover the baking dish with aluminum foil and bake in the preheated oven for 15 minutes.

Remove the foil and continue baking for an additional 10-15 minutes, or until the cheese is melted and bubbly and the top is golden brown.

Once done, remove the baking dish from the oven and let it cool slightly before serving.

If desired, garnish with fresh basil leaves before serving for a burst of flavor and color.