Preheat your oven to 400°F (204°C) and grease a 9 x 13-inch baking dish with olive oil.

Cut the zucchinis in half lengthwise and scoop out the insides, then place them in the prepared baking dish, skin-side down.

In a large skillet over medium heat, warm about a tablespoon of olive oil, then add the ground beef and cook for 3-5 minutes, breaking it up as it browns.

Stir in the diced onion and minced garlic into the skillet with the beef, cooking for an additional 2-3 minutes.

Incorporate the fire-roasted diced tomatoes, taco seasoning, kosher salt, and black pepper into the skillet and cook for 2 minutes.

Spoon the savory beef filling into each hollowed zucchini half generously.

Bake the filled zucchini boats in the preheated oven for 20-25 minutes.

During the last 5 minutes of baking, sprinkle sharp cheddar cheese over the beef mix on top of the zucchini boats.

Once baked, remove them from the oven and garnish with fresh parsley before serving.