In the bowl of a food processor, combine the flour and salt. Pulse 2 or 3 times to combine. Add the butter pieces and pulse until the mixture resembles a coarse meal.

Transfer the flour mixture to a large bowl. Drizzle in the ice-cold water and vinegar. Mix with a fork, adding more ice water by the tablespoonful as needed. Mix until the dough comes together to resemble a ball of rags. Turn out onto a lightly floured work surface and lightly knead until no dry flour is visible. Shape into a disk and wrap in plastic. Chill in the refrigerator for 1 to 2 hours.

In a large bowl, gently toss the tomatoes, garlic, and 1 teaspoon of salt. Set this aside while you prepare the dough and cheese so the tomatoes can release their moisture.

Unwrap the dough and roll it out on a lightly floured sheet of parchment paper to a 14-inch round that is approximately 1/8-inch thick. Transfer the parchment and dough to a sheet pan.

Drain the tomatoes on paper towels.

Distribute the cheese over the center of the dough, leaving a 1-1/2-inch area free at the perimeter. Arrange the tomatoes and garlic over cheese. Bring the edges of the dough up and over the filling, overlapping as needed to create a border to encase the filling. Place the galette in the refrigerator for 15 to 30 minutes to chill.

Preheat the oven to 400°F.

Brush the edge of the dough with the beaten egg. Sprinkle the tomatoes and crust with flaky or sea salt and pepper.

Place the galette in the hot oven and bake for approximately 50 minutes or until the crust is golden brown and the filling is bubbling.

Remove the galette from the oven. Slide it onto a clean cutting board and allow it to rest for 5 minutes. Sprinkle with the lemon zest and herbs. Slice the galette into quarters and serve while warm.