Prep the Zucchini: Slice your zucchini into thin, uniform rounds. Arrange them flat on paper towels and sprinkle lightly with salt. Let them sit for 10–15 minutes to sweat, then firmly pat them dry with clean paper towels to remove all excess moisture.

Cook the Beef Base: Preheat your oven to 375°F (190°C) and lightly grease a 9x13-inch baking dish. Heat the olive oil in a large skillet over medium-high heat. Add the diced onion and minced garlic, sautéing for 2-3 minutes until soft and fragrant. Add the ground beef, breaking it up with a wooden spoon, and cook until fully browned. Drain any excess grease from the pan.

Season and Simmer: Turn the skillet heat to medium-low. Stir in the sugar-free marinara sauce, Italian seasoning, garlic powder, onion powder, paprika, salt, and black pepper. Allow the meat sauce to simmer gently for about 5 minutes so the flavors fully combine.

Assemble the Casserole: In your prepared 9x13 baking dish, layer half of the dried zucchini slices along the bottom. Evenly spread half of the seasoned meat mixture over the top, then sprinkle with 1 cup of the shredded mozzarella cheese. Repeat the process with the remaining zucchini slices and the rest of the meat mixture.

Bake and Melt: Top the casserole evenly with the remaining ½ cup of mozzarella and the 2 tbsp of grated Parmesan cheese. Bake uncovered in the preheated oven for 25 to 30 minutes until the zucchini is tender, the sauce is bubbling vigorously at the edges, and the top cheese layer turns a beautiful golden brown.

Rest and Serve: Remove the dish from the oven and let it rest on the counter for 5–10 minutes to allow the layers to firmly set. Garnish with fresh chopped parsley before slicing and serving warm.