In a food processor, add the flour and salt and pulse a few times to combine. Add in the cold butter and pulse a few times until the mixture is coarse and crumbly.

Gradually add in the ice water, a 1/2 Tablespoon at a time, until the dough sticks together nicely. Shape the dough into a disc and wrap it in plastic. Refrigerate for at least 1 hour.

Preheat the oven to 400℉. Line a baking sheet with parchment paper and set aside.

Line a second baking sheet with paper towels. Slice the tomatoes and lay them on the paper towels. Sprinkle them with Kosher salt for five minutes. Meanwhile heat up a small skillet with the olive oil. Saute the garlic and spinach for 1 minutes. Season with 1/2 teaspoon of salt. Saute for a few more minutes until the spinach is soft and wilted.

Roll out the dough (store-bought or homemade Galette) on a lightly floured surface to make a 14" circle. Place the dough on the parchment lined baking sheet. Brush the dough with the remaining olive oil, but don't go all the way to the edge. Leave at least a 2" buffer from oil to edge.

Evenly spread out the cheese on top of the dough. Then spread the spinach mixture on top. Blot the tomatoes with more paper towels to make them as dry as possible. Then arrange the tomatoes on top of the spinach and cheese.

Season the tomatoes with salt, pepper, and dried oregano. Sprinkle the parmesan cheese on top. Fold the outer 2" edges of the dough onto the outer tomato edges, forming dough pleats as you go.

In a small bowl, mix the egg with the water. Brush the out edges of the dough with the egg wash. Sprinkle more salt on the edges.

Bake for 30-35 minutes or until the crust is a lovely golden brown and the tomatoes have softened and begun to caramlize. Cool on the baking sheet, on a baking rack for 15 minutes before cutting. Serve with fresh basil leaves.