Make the Pie Dough

Combine the dry ingredients: Add the flour and salt to a food processor fitted with the blade attachment. Pulse one or two times.

Add butter and shortening: Cut the butter into small pieces (about 1-inch), then add to the food processor. Cut the shortening into 2-4 pieces and add to processor. Pulse until everything is combined and the mixture resembles coarse breadcrumbs.

Add cold water: Drizzle the ice water into the food processor, pausing to pulse periodically. After several pulses the dough should start to form into a ball. The dough should stick together if you pinch it.

Chill: Remove the dough from the food processor and wrap it in plastic wrap. Gently smush it together briefly with your hands to make everything finish forming a cohesive dough. Then pat it into a round and chill in the fridge for at least one hour.

Assemble and Bake

Preheat the oven to 400F. Line a baking sheet with parchment paper.

Prep the tomatoes. Slice them about 1/4 inch thick. Place them in a large bowl and gently toss the tomatoes with 1 tablespoon olive oil and 1 teaspoon kosher salt. Set aside.

Roll out the dough. On a well floured countertop, roll the dough out into a 13-14 inch rough circle. 

Transfer the dough to your baking sheet. The easiest way to do this is to gently roll the dough over your rolling pin and then lift the dough on the pin. You can also roll out the dough between two sheets of parchment paper and then just transfer the parchment paper to your baking sheet. If you do this, you don’t need to line the sheet before hand. Remove the top layer of parchment paper.

Blot the tomatoes. Drain the excess tomato juice and transfer the slices to a plate lined with paper towels. Gently blot the tomatoes with additional paper towel to soak up the extra liquid. Set aside.

Fill the dough. Spread the mayo over the dough, leaving a 4-inch margin. Top with Ritz cracker crumbs. Sprinkle with cheddar cheese, then add the tomato slices. You can arrange the tomatoes in a pretty pattern if you like. Add your chopped fresh herbs  all over the top of the slices, then drizzle the herbs with the remaining tablespoon of olive oil. 

Fold up the edges. Gently fold the edges of the dough over the filling.

Add egg wash. Combine 1 egg with 1 tablespoon of water. Whisk well. Brush over the dough. 

Bake. Place the galette in the oven and bake at 400F for 50-60 minutes, rotating halfway through. Check the galette periodically. If it is browning too fast, loosely cover with aluminum foil once desired color is reached. This way the filling has extra time to cook without the crust over browning.

Cool and serve. Remove from the oven and let cool 5-10 minutes. Serve.