In a mixing bowl, combine flour and salt, then cut in cold butter using a pastry cutter or your fingertips until the mixture resembles coarse crumbs. Add cold water gradually, mixing until the dough forms a ball. Wrap in plastic wrap and chill in the fridge for at least 30 minutes to ensure a flaky crust.

While the dough chills, preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper to prevent sticking.

After chilling, lightly flour your work surface and roll out the dough into a round shape, about 12 inches in diameter, with a thickness of roughly 1/8 inch.

Transfer the rolled dough onto the prepared baking sheet and pile the sliced tomatoes in the center, leaving a 2-inch border. Sprinkle evenly with salt and fresh herbs. Fold the edges of the dough over the tomatoes.

Brush the exposed crust with olive oil. Bake for 30-35 minutes, or until the crust turns golden brown and crispy.

Once baked, remove the galette from the oven and let it cool for a few minutes. Slice into wedges and serve warm.