Make the crêpe batter: Whisk together flour and eggs in a medium bowl. Add milk and cream, and whisk until smooth. Pour through a fine strainer into a bowl, cover, and refrigerate for 2 hours or overnight.
Prepare the sauce: Use a vegetable peeler to remove rind from 2 of the oranges, avoiding pith; mince rind and set aside. Juice all the oranges and set juice aside. In a medium bowl, beat butter and 1⁄2 cup sugar on high speed of a hand mixer until light and fluffy, about 2 minutes. Add rind to butter and beat for 1 minute. Gradually drizzle in juice, 2 tbsp. of the Cointreau, kirsch, and orange flower water, beating constantly until very light and fluffy, about 2 minutes more.
Make the crêpes: Heat a seasoned crêpe pan or small nonstick skillet over medium-high heat until hot. Grease pan with a little butter, then pour in 1⁄4 cup batter. Working quickly, swirl batter to just coat pan, and cook until edges brown, about 1 minute. Turn with a spatula and brown other side for about 30 seconds. Transfer to a plate and repeat with remaining batter, greasing pan only as needed.
To serve: Melt orange butter sauce in a 12″ skillet over medium heat until bubbling. Dip both sides of one crêpe in sauce, then, with best side facing down, fold in half, then in half again. Repeat process with remaining crêpes, arranging and overlapping them around the perimeter of the pan. Sprinkle with remaining sugar. Remove pan from heat, pour remaining Cointreau and the cognac over crêpes, and carefully ignite with a match. Spoon sauce over crêpes until flame dies out, and then serve immediately.