For the crust, combine all the crust ingredients in your food processor and mix just until combined. Don’t overmix it. The mixture will still look very crumbly, but it will come together when we form it into a ball to refrigerate it, so don’t let that concern you.
Dump the mixture out onto a sheet of plastic wrap and begin to bring it together so it’s a ball. Forming it into a ball now will make it easier to roll out later. Make sure it’s fully enclosed in the plastic wrap and refrigerate for at least 30 minutes or one hour. This will allow the flour to absorb into the dough and let the dough relax, making for better flavor and making it easier to roll. In the meantime, turn your oven on to preheat at 400F.
Once the dough has rested in the fridge, you can take the dough out, unwrap it, and begin to roll it out thinly. You want to make sure to try to keep the shape round as you’re rolling and make sure you don’t go over the edges as you’re rolling, as this will result in uneven sides. If it’s too sticky for any reason, add a bit of flour to your work surface and a bit on top of the dough.
When the dough is rolled out, use your rolling pin to wrap the dough around the pin to help lift it to your prepared tart pan. Begin to flatten the bottom and sides with your fingers, and then use a measuring cup to flatten as needed. Use a paring knife to cut off any excess dough hanging off the edges. Try to get the dough as flat and even as possible so it bakes evenly. Use a fork to dock the bottom of the dough and some of the sides. Docking the dough prevents steam from being trapped in the dough, so it won’t bubble up as it bakes. Brush with the beaten egg white.
Bake at 400 for around 10 minutes or until baked and lightly golden brown. After baking, set it to the side to cool while you work on the filling. Turn the oven down to 350F and keep the oven on so it’s preheated for the tart.