Preheat the oven to 200 °C/ 400 °F.
Slice the eggplant into 1/2 inch (~ 1 cm) slices and place on a baking tray.
Grease with 1/4 of melted ghee, season with a pinch of salt and place in the oven.
Cook for about 20 minutes.
If you're using frozen spinach, let it defrost at room temperature for a couple of hours (or microwave).
If you're using fresh spinach, you'll need to blanch it.
Bring a pot of water to a boil over high heat.
Fill a bowl with ice and water or simply with cold water.
Place the spinach leaves into the boiling water and cook for 30-60 seconds.
Transfer the leaves immediately into the iced water using tongs or a strainer.
One it cools down, remove from the cold water.
Drain the excess water by placing the spinach in a strainer and squeezing the excess fluids out.
Meanwhile, prepare the Marinara sauce by following this recipe.
When the eggplant is done, remove from the oven and set aside.
Reduce the temperature to 180 °C/ 360 °F.
Prepare the omelettes.
Crack one egg at a time in a bowl, season with a pinch of salt and mix well.
Pour on in a hot pan greased with ghee (use the remaining 2 tablespoons of ghee for greasing the pan as needed) and swirl around to create a very thin omelette.
Cook for just about a minute or two, until the top is firm.
Place on a plate and repeat for the remaining eggs.
Make a total of 6 omelettes.
Start assembling the lasagna by placing a layer of 2 omelettes on the bottom of a banking dish (I used a 9 x 12 inch / 23 x 30 cm baking dish).
You can create less layers if you like - it's totally up to you.
Just make sure you top the lasagna with some mozzarella and parmesan.
Spread a third of the Marinara sauce on top of the omelettes.
Add a third of the eggplant slices, ...
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a third of the grated mozzarella cheese, half of the spinach...
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and half of the crumbled feta cheese.
Top with 2 more omelettes.
Repeat layering the lasagna: Spread a third of the Marinara sauce on top, add a third of the eggplant slices and a third of grated mozzarella.
Add the remaining spinach and feta cheese.
For the last layer, add the remaining omelettes, marinara sauce, eggplant slices and mozzarella cheese.
Top with all of the grated parmesan cheese and place in the oven.
Bake for 25-30 minutes.
When done, the top gets crispy and golden brown.
Remove from the oven and set aside to cool down.
Eat immediately or let it cool down and store in the fridge for up to 5 days.
The lasagna can be served either warm or cold.