Step 1

Line 2 trays with non-stick baking paper. Place 2 wire racks over the trays. Preheat the oven to 100°C. Cut tomatoes in half lengthways and place, cut-side up, on the racks.

Step 2

Brush the cut side of the tomatoes with the oil.

Step 3

Sprinkle tomatoes evenly with sea salt and oregano. Bake in preheated oven, swapping trays halfway through cooking, for 4-4 1/2 hours or until the tomatoes start to shrivel around the edges and are about half the original size. (Cooking time will vary slightly depending on the size of the tomatoes.)

Step 4

Remove the tomatoes from the oven and set aside on the racks to cool. Store in an airtight container, in single layers between sheets of non-stick baking paper, in the fridge.