Here is my simple tomato sauce recipe, works perfectly with pasta dishes or when thickened can be used as a pizza sauce.
Blend the tomatoes, capsicum, chilli, onion and carrot with a bit of water until smooth. Heat a the oil in a pan, then add the garlic paste, followed by the tomato paste.
Once that's cooked for a couple of minutes, add the blended mixture and simmer. Add salt and sugar followed by a bit of tandoori masala or cumin powder or oregano or you can just leave it plain and unspiced according to your taste.
Let it simmer until thick and all the water is gone. Taste and adjust if needed. Then use accordingly!