Tomatoes – Do You Need to Cook Tomato Puree?

Tomato puree is concentrated tomato. So where it is called for in conjunction with other tomato products, be they fresh or tinned, it is an attempt to increase the tomato flavour/presence in the dish without increasing the bulk or water inherent in less concentrated products.

Additionally the flavour of puree, having gone through a reduction process is somewhat different, more intense and rich than straight tomatoes.

Indeed, canned tomatoes tend to be surrounded with juice that is more reduced than would occur naturally. Which is part of why they are used against fresh tomatoes.

Tomato paste is just tomatoes with the water removed, essentially. I'd slice the tomatoes in half and roast them (cut side up) at 350 degrees F for an hour (this will concentrate the flavour nicely and you can add s&p/olive oil/herbs/garlic if you want). Then mash them through a sieve or food mill to get a smooth consistency. Then put that tomato puree in a pot and just boil them down until it's as thick as you want. As it gets thicker, you'll need to stir it regularly to prevent it sticking to the bottom of the pot and burning.