How do you make your own tomato purée

Peel and skin the tomatoes. You can do this easily by bringing a pot of water to boil, cut an "X" in the bottom of the tomatoes and when the skin starts to visibly crack scoop them out and plunge into cold water. Take off the skin and stick them in a blender with salt (for flavor) and liquefy. This is a nearly raw product so hopefully your next step is to cook them.

This is my recipe for homemade tomato paste. To make puree, I would not cook it down as much. Hope this helps!