Pre-heat your oven to 375F. Bring the butter and water to a boil.
Dump the flour at once.
Blend until the dough comes unstuck from the sides.
Keep heating while kneading with a spoon for 3 minutes.
Transfer to mixer and beat so help it cool.
When it stops steaming, add the egg and egg white regularly.
At first when adding the eggs, the dough will be gummy.
After beating, the dough will be smooth and ready.
Drop on ungreased cookie sheet in heaping tablespoons. Bake at 375 for 25 minutes.
When the pastries have cooled, you can refrigerate them. Fill in with the room-temperature marshmallow "creme" and the blueberries just before serving; the marshmallow
becomes stiff when refrigerated.
Looking pretty and redy to eat.