Wash a large metal bowl and a box grater. Dry well. Place the bowl, grater, and the butter in the freezer for 20 minutes.

Take out the bowl, grater and butter from the freezer. In the bowl, whisk together the flour and salt. Then grate the butter into the flour and, using your fingers, rub the butter Ito the flour until the mixture looks like small peas.

In the center of the flour/butter mixture, add the sour cream and cheddar cheese. Use a fork to mix it all together until the dough is moist. Turn the dough out onto a lightly floured counter and gently knead the dough a few times and form into a disk. Cover the disc with plastic and chill in the fridge for 2 hours or overnight. Overnight is better.

Take the dough out of the fridge and place on a lightly floured counter. Roll out the dough until it is a rectangle about 3/4" thick. Then fold the dough into thirds, turn the dough clockwise, and roll it out again until it's a 3/4" thick rectangle. Repeat this at least 6 times, always moving clockwise, until you have many layers and the dough is really smooth.

Cut the finished dough in half, cover each in plastic wrap, and chill in the fridge until using for up to 2 days. It can also store in the freezer for up to 3 months.

In a food processor, process the walnuts, cloves, and a pinch of salt until it is kind of chunky, Then add in the basil leaves. Process while slowly adding in the olive oil until it is smooth.

In a medium size bowl, stir together the Parmesan and Pecorino and Romano cheeses with the salt. Stir in the pesto and mix until well blended. Set aside.

Preheat the oven to 350℉. Lightly grease a 9" deep dish pie plate.

Wash and slice the tomatoes, placing them on a baking sheet lined with lots of paper towels. Sprinkle salt over the tomatoes and let them rest for 10 minutes. This will release excess moisture.

In a medium bowl, mix together the ricotta cheese and pesto until combined.

Using one disc of dough, roll it out on a lightly floured counter with a rolling pin. Roll the dough into a circle that is about 1 1/2" thick and 10" in diameter. Lay the dough into the pie plate and leave the edges hanging off for now.

Spread the ricotta pesto mixture over the bottom of the pastry. Place the tomato slices over the cheese, layering as you please, and sprinkle the top with a pinch of salt, pepper, dried basil, dried oregano and a bit of olive oil drizzled over top. Fold the extra dough edges in for a more rustic tart, or flute the edges of the dough.

Use the egg wash over the outer edges of the tart and bake for 15-20 minutes, or until the dough is golden and crispy and the cheese is lightly bubbling in the center.

Let the tart rest for at least 20 minutes before serving.