Beat butter with 1/2 cup sugar until thoroughly mixed.
Add lemon juice, orange juice and 1/4 cup liqueur while continuing to beat.
Heat orange butter until bubbly.
Dip crepes in hot orange butter and stack.
Sprinkle top with 1 tablespoon sugar.
Heat liqueur and cognac.
Pour over stacked crepes and ignite.
Spoon sauce over crepes until flames die.
Cut and serve immediately.