Wash and ore your tomatoes, then set the aside. Make sure you don't prep more than you can fit into your dehydrator in a load.

Slice your tomatoes as thin as you can (to reduce drying time), but most importantly make sure your slices are as uniform as they can be.

Place your slices either directly on your dehydrator trays, or onto silicone liners, depending on your machine. I find they dry faster directly on the trays, but they also stick more, which is why the liners are helpful. Make sure the slices are single layer and not overlapping.

Dehydrate your tomato slices at 135 degrees for anywhere from 6-12 hours, depending on how thick/thin your slices are. Flipping your tomato slices halfway through will significantly reduces your drying time and help them dry more evenly.

Check your tomatoes frequently to check for dryness. Fully dehydrated tomatoes should feel dry and leathery, slightly crispy. If they're turning a dark color or overly crispy they might be overdone. If they're soft or still feel moist at all, they're not done yet.

Make sure your tomatoes are completely cool before sealing in an airtight container. Any heat left in the tomatoes can lead to moisture building up, which can allow them to go bad.

Condition your tomatoes for about a week by vigorously shaking them every day. I like to use a half gallon jar for this, filling it only 1/2-3/4 full to allow room for shaking. Conditioning is a really important step in the dehydrating process, so don't skip this step. Almost 100% of the time when I hear of someone being discouraged with their dehydrated food, it's because they didn't condition it properly after dehydrating. See more about conditioning below.

Store your dehydrated tomato slices in an airtight container indefinitely. Especially if you're planning on storing them super long-term, check them every so often to make sure there's no signs of moisture or mildew.

Dump all your washed and cored tomatoes into a blender. (Don't tell the experts, but I will even leave my cores in...)

Blend those into a liquid-y tomato smoothie (my daughter has been known to call it "vomit" because it... well... does have a resemblance, even more so depending on what kinds/colors of tomatoes you're using... I grow a lot of yellow and orange tomato varieties).

Carefully pour your tomato puree onto your lined dehydrator trays and spread it out with a spatula. DON'T pour more puree than will fit on your trays. You'll want to leave about 1/2-1 inch of space around the edges of your trays to allow it to spread and settle a bit without leaking off the trays.

Dehydrate at 135 degrees for 8-12 hours. You'll know they're done when the tomato "leather" breaks into pieces when you try to break it in half, rather than bending.

Once your tomato leather is all dry, stuff the cooled leather into a DRY blender (again) to blend it into a powder.

Condition your tomato powder in the oven. Don't skip this step or you'll have a tomato brick in a few months. Preheat your oven to 150 degrees and TURN IT OFF. Place your powder on parchment paper, on a cookie tray, and place the tray in the turned off oven for ½ an hour.