Simple Lasagna with Tomato Basil Sauce

1 medium onion peeled and coarsely chopped
1/2 cup Extra Virgin Olive Oil
2 – 28 oz cans tomato sauce (2 – 700 g bottles)
1 cup of water.
Add salt to taste. (1/1/2 Tbsp add more salt if needed after allowing sauce to simmer for 10 minutes.)
1/2 tsp pepper
6 leaves fresh Basil (add ONLY in the last 10 minutes of cooking sauce.)

24 pasta sheets (Spinach or Egg pasta)
400 g thinly sliced mozzarella cheese.
1/2 cup grated parmesan cheese

Add coarsely chopped onion and olive oil. Cover pan and allow to cook for 5 minutes on MEDIUM heat, turning the onions, as to not to burn.
Add tomato sauce,1 cup of water. Prop lid of pan with wooden spoon and allow to simmer on LOW or Warm heat for 20 minutes turning sauce occasionally. Add fresh basil leaves and stir into sauce. Remove from heat.

ASSEMBLY
Preheat oven to 350 F or 170 C
In a 9×11 cake size pan add to bottom of pan 5 ladles of sauce. Add 6 pasta sheets distributed side by side in pan. Layer with 6-8 slices of  mozzarella cheese. Add 5 ladles of  sauce to cover pasta. Add second layer of 6 pasta sheets distribute so they are side by side.  Layer with slices of cheese.

Repeat layering process of pasta, tomato sauce and cheese 2 more times. Top off last layer with sliced mozzarella and parmesan cheese.
Place in oven and allow to bake  for 30 minutes.

Remove from oven and allow to sit and cool down for 20 minutes before serving.