Using a paring knife, cut out the core of the tomatoes. Carefully scoop out the insides with a spoon. Set aside.
In a large oven safe skillet, heat oil and garlic over medium heat. Add ground beef, squash, onion, salt, pepper, and dried Italian seasoning. Stir and cook until meat is cooked halfway through.
Remove from heat and allow meat mixture to cool. Stir in half of the cheese, all of the breadcrumbs, egg, and Italian dressing. Combine well.
Evenly spoon the stuffing into the tomatoes, and place them in the skillet. Roast in the oven for 25 minutes. Remove from the oven, top with the remaining cheese. Return to the oven and broil for a few minutes until the cheese is melted and bubbly.