1. Preheat the oven to 375°F (190°C).
2. Brown the ground beef in a skillet over medium heat. Once browned, add the pasta sauce and simmer for 5-7 minutes. Alternatively, you can use leftover ground beef, such as leftover hamburgers from a cookout. Crumble them up and mix with your sauce.
3. In a small bowl, mix the cottage cheese with the egg until well combined. Set aside.
4. In a shallow baking dish, such as an 8×8 or similar size, mix the flour, salt, and pepper.
5. Spray a 9×13 baking dish with cooking spray. Dredge the slices of zucchini in the flour mixture and layer them in the bottom of the baking dish. This will use about half of the zucchini slices.
6. Spread the cottage cheese mixture evenly over the zucchini slices.
7. Top the cottage cheese mixture with half of the ground beef and sauce mixture.
8. Add the remaining zucchini slices in a single layer. If you have extra slices, set them aside; you should not make more than two layers.
9. Spread the remaining ground beef and sauce mixture evenly over the zucchini.
10. Sprinkle the shredded mozzarella cheese evenly over the top.
11. Cover the baking dish with foil and bake for 30 minutes.
12. Remove the foil and bake for an additional 10-15 minutes, until the zucchini is tender and the lasagna is bubbling.
13. Let it rest for 5-10 minutes before slicing and serving.

Enjoy your delicious Zucchini Lasagna with Cottage Cheese!