Marinara Sauce : In a pan heat oil. Add chopped garlic. Followed by chopped blanched tomatoes, tomato paste, salt and sugar. Bring everything to a boil. Add reserved water if required to get the consistency. Stir in chopped basil leaves. Switch off the gas.
Bechamel Sauce: In another pan add butter. Add few drops of olive oil. Stir in flour and mix continuously until the paste cooks and bubbles a bit. Take care not to burn. Add hot milk. Stir constantly and allow it to boil. ( try to avoid lumps by stirring constantly ).
Switch off the gas. Stir in parmesan cheese. Keep aside the sauce.
In a pan 1.5 tbsp of olive oil, Minced garlic, salt and pepper. Mix well. Add potatoes. toss well. Remove and Keep in a separate bowl. Then toss them with 1.5 tbsp of flour.
In the same bowl add chicken cubes to the remaining marinade. Mix well. Toss the chicken cubes with remaining 1.5 tbsp flour. Keep aside.
In a thick bottom pan add remaining oil (1 tbsp). When the pan is hot add the chicken cubes and toss in high heat for not more than 4 minutes. (We are going to bake it later, so it's ok if it is not cooked through)
Once the chicken looks brown on outer side, remove and keep aside. Scrape any residue from the pan.( Don't ever through the roasted residue from the pan, it's the best part)
In the same pan toss marinated potatoes. Fry on medium-high heat until they are roasted and golden brown. Remove from the pan and any of its residue. Keep aside.
Pre-heat oven to 180 degree celsius.
In a rectangular baking pan spread 1/4th of the Marinara sauce. Arrange roasted potatoes and chicken cubes in a layer. Sprinkle some chilli flakes(if using) and chopped fresh basil.
Spread 1/2 of the remaining Marinara sauce and bechamel sauce.
Layer with remaining potatoes and chicken, followed by leftover marinara sauce and bechamel sauce.
Sprinkle some more chilli flakes and chopped basil. Top with shredded Mozzarella cheese.
Cover the tray with an aluminium foil and bake for 10-12 minutes. Remove the cover and bake for 5-6 minutes more until the cheese melts.
Serve warm with some toasted rustic bread and pasta.