Serves: 24 tomato halves1) Preheat the oven to 125C/Gas Mark 1.
2) Toss the tomatoes in a bowl with the olive oil. Arrange the tomatoes, cut side up, in a single layer on a parchment or foil-lined baking sheet. Sprinkle with the salt and the fish sauce or celery salt. Bake until slightly shriveled but still plump, 5 to 6 hrs.
3) If not using immediately, refrigerate the dried tomatoes in a sealed container for up to 4 days.