Baked Brie en Croûte with Apple Compote

For the apple compote:

unsalted butter

golden delicious apples, peeled, cored and cut to ½-inch dice

sugar

grated nutmeg

To assemble:

-inch round puff pastry, rolled to ¼-inch thickness

round Brie cheese, 6-8 oz. and about 4½ inches wide, chilled

egg beaten with 1 tbsp. water

Water crackers, for serving