Preheat the oven to 200°F and position two racks to divide the oven into upper and lower thirds. Line two large baking trays with parchment paper to prevent sticking and ensure easy cleanup.

Detach the stems from the tomatoes and slice each one in half horizontally. Place them in a large mixing bowl. Just before baking, drizzle the olive oil over the tomatoes and sprinkle them evenly with kosher salt. Gently toss until all pieces are coated in the seasoning and oil.

Using clean hands or a slotted spoon, arrange the tomato halves cut side up on the prepared baking trays, ensuring they are well spaced and not overcrowded.

Slide the trays into the oven and begin the slow roasting process. Rotate the trays between the upper and lower racks approximately every hour to promote even drying. For slightly chewy, plump sun-dried tomatoes, bake for about 5 to 6 hours. For a more concentrated, leathery texture with minimal moisture at the center, extend the baking time to 7 to 8 hours.

Allow the tomatoes to cool on the trays at room temperature before transferring to storage.