1. **Sweat the Eggplant:** Place the eggplant slices on a baking sheet or wire rack. Sprinkle them generously with kosher salt on both sides. Let them sit for 30 minutes to draw out excess moisture (this prevents a watery lasagna).

2. **Preheat:** While the eggplant sweats, preheat your oven to 400°F (200°C). Grease a 9×13 inch baking dish.

3. **Roast Eggplant:** Rinse the salt off the eggplant slices with cold water and pat them thoroughly dry with paper towels. Brush with olive oil. Roast on baking sheets for 15–20 minutes until soft and pliable. Remove and lower oven temp to 375°F (190°C).

4. **Make the Meat Sauce:** In a large skillet over medium-high heat, sauté the onion in olive oil until soft (5 mins). Add the ground beef and cook until browned, breaking it up with a spoon. Drain excess fat.

5. Stir in the garlic, oregano, basil, and red pepper flakes. Cook for 1 minute.

6. Pour in the marinara sauce. Simmer on low for 5–10 minutes to thicken slightly. Remove from heat.

7. **Make Cheese Filling:** In a medium bowl, mix the ricotta, beaten egg, Parmesan cheese, chopped parsley, and salt until combined.

8. **Assemble:** Spread a thin layer of meat sauce on the bottom of the baking dish.

9. Layer 1: Place a layer of roasted eggplant slices over the sauce.

10. Layer 2: Spread half of the ricotta mixture over the eggplant.

11. Layer 3: Top with half of the remaining meat sauce and ½ cup of mozzarella.

12. Repeat: Add another layer of eggplant, the rest of the ricotta, the rest of the meat sauce.

13. **Top:** Finish with the remaining shredded mozzarella cheese.

14. **Bake:** Cover loosely with foil and bake at 375°F (190°C) for 25 minutes. Remove the foil and bake for another 15–20 minutes until the cheese is bubbly and golden browned.

15. **Rest:** Let the lasagna rest for 15 minutes before cutting (this helps the layers hold together).