To make the pastry crust, combine the flour and salt in a medium bowl. Grate the cold butter directly into the flour and toss to combine.
In a separate bowl, whisk together the egg, water, and vinegar.
Add the wet ingredients to the flour mixture and stir to combine. If the dough is too dry, add a little water just until it sticks together. Wrap the dough in plastic wrap and refrigerate it for at least 30 minutes.
Meanwhile, wash and cut the tomatoes into 1/4 inch thick slices. Place the slices on a cutting board or a baking sheet. Sprinkle them with salt.
Allow the tomatoes to sit for 15-30 minutes to release excess moisture. Pat them dry with paper towels prior to using.
Preheat the oven to 425°F. Place the dough on a sheet of parchment paper and roll it out into a 12-13 inch circle. Transfer the parchment paper and dough onto a baking sheet.
Spread the garlic and herb goat cheese evenly in the center of the dough, leaving a two-inch border around the outside.
Arrange the tomatoes in a spiral on top of the goat cheese. Fold the border of the dough over to form a crust.
Whisk the egg in a small bowl. Brush the crust with the egg wash and sprinkle on coarse salt or flaky sea salt.
Bake the galette for 20 minutes, or until the crust is golden brown. Top with your favorite freshly chopped herbs like basil, and add freshly cracked black pepper. Allow the galette to cool for at least 10 minutes, then serve and enjoy!