Add the flour, sugar, and salt to a food processor. Add the butter a few cubes at a time, pulsing until combined after each handful.

When the butter is fully combined, add in your water 1 tablespoon at a time, pulsing until the dough forms into a rough ball.

Remove the dough from the food processor and move to a floured surface. Knead the dough slightly and form it into a disc. Wrap in plastic wrap or a sealed container and chill in the fridge for at least 30 minutes.

Preheat your oven to 350ºF and prepare a baking sheet with parchment paper.

Roll out your dough on a floured surface until it's shaped into a large circle, about 12 inches in diameter. Move the dough to your sheet pan.

Place your asparagus in a large bowl and drizzle with olive oil and season with salt and pepper. Toss together until coated evenly and set aside.

In a small bowl, whisk your cheese with a spoon or spatula until smooth. Spread the cheese all over the prepared pie dough, leaving a border of a few inches clean for folding.

Tear your prosciutto into smaller pieces and arrange over the cheese evenly, then place the asparagus stalks in a neat line covering the other toppings, trimming the ends when necessary to keep an even circle.

Fold the edges of the pie dough over the toppings to form a crust, creasing the dough every few inches.

In a small bowl, whisk one egg with 1 tablespoon of water and brush the egg wash over the crust evenly. Sprinkle with flaky salt if desired.

Bake for 35 minutes, until crust is golden brown and baked through.

Melt the butter in a small bowl and add pepper and parsley flakes. Brush the butter mixture over the crust and sprinkle with parmesan cheese to finish before serving.