Preheat oven to 350 degrees F.
In a large skillet and over medium heat, add the olive oil and garlic. Lightly brown.
Add the sliced zucchini and Kosher salt. Sauté until slightly soft.
Add the chopped and drained tomatoes to the zucchini. Sauté until the tomatoes break down and the zucchini is tender. Continue cooking until most of the liquid released from the zucchini and tomatoes has been cooked down. Cooking the mixture down is an important step.
Once the mixture has been cooked down and the liquid has evaporated, add the fresh chopped basil and stir.
In a small casserole dish or 8” pie plate, add enough of the mixture to cover the bottom of the dish. Top with ¼ cup of the shredded mozzarella.
Add the remaining tomato-zucchini mixture on top and finish with the balance of the cheese.
**At this point, the dish can be made ahead and refrigerated until ready to bake and serve.**
Bake in the preheated oven for 20 minutes or until the edges begin to bubble slightly and the cheese has melted on top.
Serve with red pepper flakes if desired.