1. You could use a dehydrator or an oven. I thinly slice the tomatoes and air dry it on very warm days and I get dry crispy tomatoes in two days.
2.If using an oven, bake the tomatoes at the lowest temperature, using the oven fan if you have one. If using a dehydrator, dry on a low setting. either way, continue to dry the tomatoes until they are dry and brittle. You want the tomatoes to be brittle because that's a good sign that you have thoroughly removed the moisture from the tomatoes. If they are still flexible, they likely have a tiny bit of moisture still. It's a good idea to flip the tomatoes partway through the process, especially if using the oven.
3.Once it is completely dry, I like to cut it into small pieces and powder it and store in an airtight container
Ways to use it- sprinkle over popcorn, vegetables, cheese, winter stews, barbecue sauces, ramen bowls, grilled pineapple, top on scrambled eggs