For beer batter: Beat eggs until light and frothy. Add salt. Sprinkle in flour, then add beer and beat until lump free. Set aside for 2 hours.
For pancake batter: Combine flour, salt, and pepper in medium bowl. Make a well in center and add 1 egg and 1 yolk and milk, beating gradually. Add melted butter, beat well and set aside in cool place for 2 hours.
For bechamel sauce: Melt 2 tablespoons butter in small pot on medium-low heat. Remove from heat and stir in flour. Return to heat and cook for 5 minutes; do not let brown. Remove from heat again and gradually stir in milk. Add bay leaf, onion, mace, and parsley stalks. Increase heat and boil for 3 minutes to thicken sauce, stirring constantly. Turn to a low simmer to keep warm until serving.
For filling: Add 3/8-cup bechamel sauce to half the beer batter. Reserve remaining sauce and batter for another use. Add camembert and cream together well. Mix in mustard.
Melt remaining 2 tablespoons butter in omelet pan. Add to pancake batter and beat well. Return pan to heat and add a thin layer of batter to pan. Loosen sides from pancake and cook until underside is lightly browned. Flip and cook the other side. Repeat, making 4 pancakes. Chill pancakes.
Preheat oil in deep fryer to 375 degrees F. Divide cheese mixture between pancakes. Fold pancakes over to enclose filling. Place packages 1 at a time into hot oil and cook until golden brown, about 4 minutes. Drain on paper towels and serve immediately.