In the mixer bowl, mix water, yeast, and sugar.
Let it rest for 10 minutes.
Add the egg, salt, flour, and butter, and mix with the dough hook for 10 minutes or until the dough forms a ball and is soft without being sticky.
If it seems sticky, add a little flour.
Cover the bowl and let it rest for 20 minutes.

Preheat the oven to 400 F (200 C)

Melt the butter in a saucepan. Add the flour and incorporate it well into the butter.
Using a whisk, slowly incorporate the milk and cream.
Bring to a boil, continuing to whisk until the mixture thickens.
Season with salt and pepper, and add the parsley. Set aside.

Roll out the dough into a 10″ x 14″ (25 cm x 35 cm) rectangle.
Place the dough on a baking sheet.

Spread the béchamel sauce over the surface, leaving a 2″ (5 cm) border.
Add the asparagus and top with cheddar cheese.
Brush the edge with water and fold the edge of the dough, making a small ridge.

Bake in the oven for 15 to 20 minutes or until the dough is golden brown and cooked, and the filling is hot.