Preheat the oven to a high broil (500 F). Prepare a baking sheet with parchment paper.
Slice the ends off the eggplant then thinly slice it using a mandoline or knife. Place the slices on a baking sheet and sprinkle with salt. Broil the eggplant 5-10 minutes until lightly browned.
Remove from the oven and pat with paper towels to remove any liquid remaining. Set aside.
In a large mixing bowl, combine the ground chicken (uncooked), cottage cheese, red onion, dried parsley and egg. Stir to incorporate the ingredients thoroughly.
Spray the inside of a crockpot with cooking spray. Place 1/4 cup of marinara sauce on the bottom of the pan. It won't seem like much, but it's all you need.
Place a layer of eggplant over the marinara sauce. Over the eggplant, place 1/3 of the chicken mixture followed by 1/2 cup of the marinara sauce. Repeat this process for 2 more layers. They will be thick. Top the last layer with the remaining marinara sauce and mozzarella cheese.
Cook the lasagna in the crockpot on high 3 hours or low 6 hours. You will know the lasagna is finished if you can cut into the eggplant and it's nice and tender. You should expect to see liquid in the crockpot from the eggplant. The liquid can be discarded after making.
Slice into 6 equal pieces and serve warm.
Notes
Slice the eggplant the day before making your lasagna and store it in the refrigerator overnight. This helps reduce prep time and gives the eggplant extra time to dry out.
The eggplant is more tender and has a better texture if you cook this lasagna on low for 6-8 hours instead of on high for less time.
Don’t skip adding marinara sauce to the bottom of the slow cooker. It helps prevent the eggplant and cheese from sticking to the bottom and burning.
If you prefer, you can brown the chicken in a skillet before step 4.
Store the lasagna in the refrigerator in an airtight container up to 1 week. This will not store well in the freezer due to the moisture from the eggplant which will make the lasagna soggy and dilute the flavor.