Tomato paste. Find one called doppio concentrato but if you can't don't sweat it, just find one that you can find. Open it up and make sure that when ever you use tomato paste you never put it into something that already has liquid in it. You want to put it into something that is still at the heat of a saute pan or a roasting pan that is to say around 300 or 350 because you're looking to toast it In with the flavor, so that it adds ten times more flavor in to whatever you're putting it into. Now, that's to say that the direct heat on this tomato paste is gonna change this to something that's too sweet, to something that's sweet and complex.