Preheat the oven and get the vegetables ready.

Oven should be preheated to 375°F (190°C).

Clean and dry the zucchini and the yellow squash then cut them into thin, even slices, about 1/8 to 1/4 inch thick.

Put the slices into a large bowl and lightly season them with salt. Let them stand for approximately 10 minutes, then carefully pat them dry with paper towels to get rid of the excess moisture.

Prepare the Creamy Garlic Sauce

Heat the butter in a small saucepan over medium-low heat.

Cook the minced garlic for 30 to 60 seconds until it is fragrant.

Add the heavy cream and stir it in. Then mix in the Italian seasoning, paprika, black pepper, and one quarter cup of the Parmesan cheese.

Stir it gently until all the ingredients have been mixed and the sauce has warmed through. Do not boil it heavily.

Arrange the Vegetables

Grease a baking dish lightly with olive oil or butter.

Place the slices of zucchini and yellow squash in overlapping rows or in a circular pattern, taking turns between the two vegetables.

Prepare the cream sauce

Evenly pour the creamy garlic sauce over the vegetables that have been arranged.

Tip the baking dish gently so that the sauce can flow between the slices of vegetable.

Add the Cheese

Cover the vegetables with the leftover Parmesan cheese.

Add the shredded mozzarella cheese on top in an even layer.

If you want an extra crispy topping, cover the cheese with some breadcrumbs.

Bake

Put the dish into the oven which has already been heated and bake it open for 30 to 40 minutes until the vegetables are tender and the cheese is golden brown and bubbling.

If you want a golden top then broil for 1 to 2 minutes towards the end, keeping a careful eye on the food while you're broiling it.

Rest and Serve

Take the gratin out of the oven and let it stand for 5 to 10 minutes.

Finish by chopping some parsley fresh and serve it warm.