Preheat oven to 250ºF, and line a baking sheet with parchment paper. In a large bowl, combine tomatoes and olive oil. Season with sea salt and black pepper. Gently toss to coat.

Place tomato slices on parchment paper. Sprinkle with nutritional yeast and chopped basil.

Bake for 6-8 hours. Since oven times may vary, check your tomatoes after 4 hours. If you want a juicier tomato, remove from oven after 6 hours. If you like a chewier tomato, bake the full 8 hours. Allow tomatoes to cool for about 2 hours. Store in an airtight container.