Croûte Champêtre

Preheat the oven to 425 F.
Melt half the butter in a saucepan and cook the sliced leek for 2-3 minutes.
Remove the leek from the pan and set aside.
Add the rest of the butter and the flour and stir well.
Add the milk and whisk until thickened.
Add the cheese, salt, pepper, and nutmeg to the sauce.
Add the leek and ham and then pour into a 4-cup baking dish.
Turn the baking dish upside down, place it on top of the dough, and cut around
the dish. Pour the mixture into the dish. Form a band from some of the extra
dough and place it on the edge of the dish (see photo), using water to make it stick
to the dish’s side if necessary. Place the sheet of dough on top of the dish, making
some incisions to release the steam.
Use the leftover dough to form decorations to place on the top. With a knife,
make incisions all away around the dough. Baste with the beaten egg (optional).
Bake in the oven at 425 F for 15 minutes and then for 20 minutes at 375 F.