In a blender, combine all of the crêpe ingredients and pulse for 10-20 seconds to mix batter. Place the crepe batter in a bowl, cover with plastic wrap and place in refrigerator for 1 hour.
Remove batter and heat a non-stick pan.
Brush a little butter to coat bottom of pan. Pour 1/3 cup of batter into the center of the pan, and swirl to spread evenly. Cook for 30-60 seconds and flip. Cook for another 10 seconds and remove to cutting board. Lay crêpes out flat so they can cool. Continue until all batter is gone. Cover with plastic wrap.
Add 3 tablespoons of Cognac to non-stick pan. Heat pan to medium high and ignite Cognac and shake pan until flames subside. Now, add butter, sugar, orange zest and orange juice to cognac; simmer briskly over high heat, whisking occasionally, until many large bubbles appear and mixture reduces to a thick looking syrup, 3 to 5 minutes. Remove from heat and stir in zest, Grand Marnier, and remaining cognac into sauce. Cover to keep warm.
Fold each crêpe in half, then in half again to form wedge shape. Arrange folded crêpes on oven tray. Sprinkle crêpes evenly with a little extra sugar. Place tray in oven and broil until sugar caramelizes and crêpes turn spotty brown, about 3-5 minutes. (Please keep an eye on crepes, as they can scorch; turn pan as necessary.) Remove pan from oven and transfer crêpes to individual serving dishes and drizzle with sauce. Serve immediately.