I buy no salt added organic tomato paste then add a ton of parsley, garlic, thyme, pepper....and then spread it on with a spatula. The reason behind using parchment paper is tomatoes dye dryer trays.
It is also good to add in sauteed fresh garlic and diced onions.
It is honestly one of the easiest things to make :-) And if all you want is plain tomato powder, even easier: open can, spread. Heh!