For the crust

1. In a food processor, add the flours and salt and pulse a couple of times to blend.
2. Add the cubed butter over the dry ingredients and pulse until the butter is cut into the flour.
3. Add a little of the ice-cold water and pulse, add some more and pulse. Continue until all the water is in, pulsing and stopping to scrape the sides of the bowl until the dough forms curds that hold together when you pinch them.
4. Turn the dough onto a surface and knead it gently just to bring it together. Form it into a ball, flatten it, then wrap in plastic, and set in the fridge to rest for about 2 hours.

For the filling

1. While the dough is resting in the fridge, wash the Heirloom tomatoes, then slice them into about 1/4 inch thick rounds. The small ones just cut them in half.
2. Place them in a big bowl, and dress them with evo oil, minced garlic, salt, pepper, minced herbs.
3. Gently toss the tomatoes, and let sit for 20-30 minutes, while you stretch the dough (they will start releasing their liquid).

Assembly

1. Take the dough out of the fridge and leave it at room temperature for about 10 minutes. Then, roll it in between two sheets of parchment paper, into a circle about 11-12 inches in diameter.
2. Sprinkle the Parmigiano and Gruyère on the bottom of the galette, leaving a couple of inches at the border.
3. Arrange the sliced tomatoes onto the cheese, leaving the border empty.
4. Lift the bare border of dough and fold and pleat it over the tomatoes. Add a few sprigs of thyme or basil.
5. Slide the parchment with the galette onto a baking sheet.
6. Brush the egg wash over the border, then refrigerate while you preheat the oven to 400°F (200°C).
7. Bake the galette for 35-40 minutes, or until the crust is golden and the tomatoes tender.
8. When done, transfer the baking sheet to a rack to cool.