I have been experimenting with Cookpad Maryam’s brilliant no-salt tomato powder recipe from Isfahan. She sundries tomato slices, we sundry tomato wedges.
The direct contact between wet tomatoes and a hard surface in the open air could create mold here. I laid the wet slices on paper towels in the sun in the morning.
They dried enough in one day on the paper in the sun so the tops were not sticky anymore. I flipped them over daily and had dried brittle tomatoes in four days.
Sundrying reduces the tomato weight by 90%. I dried ten pounds of beefsteak size tomatoes to make one pound tomato powder. My food processor makes chunks to dry further, my coffee grinder makes the powder.
One teaspoon of powder makes a delicious cup of soup in two minutes.