Make a cross (x) on the bottom of each tomato.
Place the tomatoes in a large pan and fill enough water to fully submerge the tomatoes. Cover the pan and cook the tomatoes for 7-8 minutes.
Drain the water and transfer the tomatoes to a bowl filled with ice water. Once cool, remove the peels of the tomatoes and roughly chop them.
Transfer half of the chopped tomatoes to a processor/mixer and blitz till you have a puree. Set aside the puree and remaining chopped tomatoes.
In a pan, add some oil, minced garlic and onions and sauté for 2-3 minutes. Add the prepared tomato puree, chopped tomatoes, chili powder, black pepper, chili flakes, oregano, sugar and salt. Cover and let it cook while stirring in between till all of the water evaporates and you have a chunky sauce.
Switch off the flame and add chopped basil. You could also add more fresh herbs like thyme, parsley, cilantro etc if you like.
Let cool then use over pizza dough or store in a clean glass jar.