Cut the eggplants in halves lengthwise. Remove the soft part inside the eggplant with a spoon but don't discard it: you will use in the filling. You should end up with 4 boats of eggplant (the thickness of each boat should be around ½ in). Then generously sprinkle salt on the eggplant boats and also the inside of the eggplant that you removed. Leave it to rest for 30 minutes.
After 30 minutes, wash away the salt and the dark-ish liquid. Grease the bottom of the baking dish and place the four eggplant boats. Bake in the oven at 400℉ for 15 minutes.
While the eggplant boats are baking in the oven, prepare the filling. Cut the inside of the eggplant in small pieces. Heat 2 tbsp of olive oil in the frying pan. Add finely chopped onion and cook for a couple of minutes until it becomes soft and transparent. Then add spinach (defrosted, excess water squeezed out) and chickpeas (drained and rinsed). Cook for a few minutes, then add the Thai red curry, tomato paste, salt, and pepper. Cook for a few minutes more.
When the 15 minutes have passed, take the eggplant boats out of the oven. Fill the boats with the chickpeas and spinach mix using a spoon. Then crumble the feta cheese on top. If you like baked tomato, you can put a couple of slices on top of each boat. Return to the oven for another 10 minutes or until the feta cheese gets brown edges. Plate the stuffed eggplant and garnish with chopped fresh parsley.