Bring 2 liters water to a boil in a large pot. Add salt as needed.
When the water comes to a boil, add pasta.
Cook al dente following the instructions on the pack.
Drain off in a colander and rinse to remove extra starch.
Heat 1 tbsp olive oil.
Saute onions on a high flame just for 2 mins.
Set them aside to cool.
To the same pan, add ripe tomatoes and saute for 2 to 3 mins.
Tomatoes must turn soft. Tomatoes must turn soft.
When cooled, add them to a blender jar.
Blend to a smooth or coarse paste. 
We prefer smooth. Set this aside.
Put back the same pan on the stove with another 1 tbsp oil. 
When hot saute garlic and red chili flakes until they turn fragrant.
Add chopped onions. Saute until the raw smell goes away.
Add the puree and salt.
Mix and cook on a medium heat until the sauce thickens.
Add the cooked pasta.
Saute until well combined.
Add crushed pepper. 
Serve pasta in red sauce hot.
