Preheat oven to 375 degrees.

Slice zucchini 1/8" thick and pat each slice dry with a paper towel. Lightly salt each slice on both sides.

Grill zucchini slices on medium heat for 1-2 minutes each side so that the moisture cooks out. Place on paper towels and pat each slice dry.

Meanwhile, make the sauce by melting the butter and cooking the garlic until fragrant. Whisk in flour. Slowly add the milk, whisking until smooth. (If sauce looks thin, add more flour 1 tablespoon at a time.)

Once the sauce has thickened, pour half on the bottom of a large baking pan. Layer zucchini slices on top.

Combine the ricotta, 1 cup of the mozzarella, egg, parmesan, salt, pepper, and seasoning. Mix well.

Spread half of the ricotta mixture on the bottom layer of zucchini slices. Top with more zucchini slices, followed by the remaining ricotta mixture. Add the last layer of zucchini.

Pour remaining sauce on top of the final zucchini layer. Top with remaining mozzarella cheese. Sprinkle with additional parmesan if desired.

Bake uncovered at 375 degrees until bubbling and the top is lightly browned, about 50 minutes.