Coat a shallow baking pan with olive oil.(9x13 or a turkey roasting pan are good). Cut up ripe tomatoes into chunks removing the cores to fill the pan. Bake slowly @300deg. turning when the tops of the tomatoes look a little browned. Continue until it’s thick enough for you. You can use as-is or strain out skins and seeds through a Squeezo, or Folley mill. Roasting imparts an almost carmelized sweetness to the sauce and darkens it a bit.