In a bowl, mix the chicken tikka masala, ginger garlic paste, and lemon juice, then add the chicken slices and coat well before covering and marinating for 15 minutes.
Heat oil in a grill pan and cook the marinated chicken fillets for 6 to 8 minutes on each side, flipping a few times until fully cooked and nicely charred.
Place a hot piece of charcoal in a small foil cup, set it in the pan with the chicken, drizzle a bit of oil on the coal, cover the pan tightly, and let it smoke for 2 minutes, then remove and let the chicken cool.
Chop the smoked chicken roughly and set it aside for layering later.
In a separate saucepan, sauté chopped onions in oil until soft, add garlic and cook until fragrant, then stir in the tomato puree, spices, bouillon, oregano, and water, cover, and simmer for 5 to 6 minutes until thickened.
To make the white sauce, melt butter in a pan, whisk in flour and cook for about a minute, then slowly add milk while whisking to avoid lumps, stir in black pepper, bouillon, oregano, and salt, and cook until smooth and creamy.
Boil the lasagna sheets until ¾ cooked, then drain and set aside, making sure they don’t stick together.
In a baking dish, layer red sauce, lasagna sheets, more red sauce, chopped chicken, white sauce, cheddar, mozzarella, capsicum, and onion, then repeat layers as needed ending with cheese on top and a sprinkle of oregano and red chili.
Fill a large pot with 1 pack of salt, place a wire rack or steamer stand inside, cover, and preheat on medium flame for 15 minutes, then set the baking dish on the rack, cover, and cook for 12 to 15 minutes until bubbly and melted