Before you start, preheat oven to 220°C (or 200°C fan bake). If you do not have an ovenproof fry-pan, set aside a large baking dish.
Prep eggplant and toss on a lined oven tray with oil. Season with salt and pepper and roast for about 20 minutes, until tender.
Prep onions and lentils. Heat oil in a large ovenproof fry-pan on medium-high heat. Cook onion for about 3 minutes, until tender. Add Italian herbs and tomato paste and cook for about 30 seconds, until fragrant.
Add salt, tomato passata and water measure to pan and bring to a simmer. Simmer for about 5 minutes, until thickened. Remove from heat, stir through lentils and season to taste with salt and pepper. Transfer to baking dish, if using. Set aside.
Crumble ciabatta into bite-sized pieces, prep feta and toss both in a medium bowl with mozzarella.
When eggplant has cooked, remove from oven. Cover lentils with sliced of eggplant. Sprinkle over crumble and bake for about 10 minutes, until golden.
Prep cucumber and toss in a large bowl with mesclun and balsamic vinegar. Season to taste with salt and pepper.
Serve eggplant parmigiana with salad on the side.