Preheat your oven to 375°F and lightly grease a small baking dish with olive oil cooking spray.
In a skillet over medium heat, spray a little olive oil cooking spray and sauté the diced onion and minced garlic until softened, about 2-3 minutes.
Add lean ground turkey to the skillet and cook until browned and fully cooked, breaking it up with a spatula as it cooks.
Meanwhile, slice the zucchini lengthwise into thin strips, which will serve as your lasagna 'noodles'.
In the baking dish, arrange a layer of zucchini slices, then spread a thin layer of tomato sauce over the zucchini.
Top the sauce with the cooked ground turkey and sprinkle evenly with low-fat mozzarella cheese.
Beat the egg in a small bowl and drizzle over the layers to help bind the ingredients together.
Repeat the layers if your dish size allows, finishing with a topping of cheese.
Bake for 20-25 minutes until the cheese is melted and the zucchini is tender.
Remove from the oven and let it rest for a few minutes before serving to allow the flavors to meld.