Grab everything you need before getting started.
**For the crêpes:**
In a medium bowl, whisk together the eggs, flour, milk, sugar, and salt until smooth. The batter will be thick at this stage, don't worry!
Add the water, oil, and melted butter and whisk it all together until well combined.
Heat up your 10-inch crêpe pan or nonstick skillet over medium-high and brush it with some butter.
Pour in about 3 tablespoons of batter and quickly tilt the pan around to spread the batter evenly. You have to work fast here!
Cook until you see the edges curling up and browning, about 45 seconds.
Flip the crêpe with a long spatula and cook another 10 to 15 seconds, just until a few brown spots appear on the bottom.
Transfer your crêpe to a baking sheet and repeat the process for about 9 more crêpes. Make sure to wipe the skillet clean and add a bit more butter between crêpes if needed.
**For the orange-butter sauce:**
In a food processor, mix together the butter, 1/3 cup sugar, and orange zest.
With the processor running, slowly pour in the orange juice until it's all incorporated.
Spoon this butter mixture into a 12-inch flameproof skillet and cook over medium heat, stirring occasionally, until it starts bubbling, about 2 to 3 minutes.
Keep cooking and stirring occasionally until the mixture becomes syrupy, about 3 minutes more.
Reduce the heat to low.
Working with one crêpe at a time, dip both sides in the sauce using 2 forks or silicone spatulas, then fold into fourths with the prettiest side facing out.
Lift it up to let excess sauce drip off, then transfer to a baking sheet. Repeat with all the remaining crêpes, scraping down the sides of the skillet as needed.
Transfer all the folded crêpes back to the skillet, overlapping them slightly to fit all 10. Scrape any extra sauce from the baking sheet back into the skillet.
Sprinkle the crêpes with the remaining 2 tablespoons of sugar.
Increase the heat to medium.
Add the Grand Marnier and Cognac, then carefully ignite the sauce with a long-handled lighter. BE CAREFUL here!
Carefully spoon the flaming sauce over the crêpes using a long-handled, heatproof spoon until the flames die down, about 30 seconds.
Transfer the crêpes to a platter and spoon any extra sauce over the top.
Serve immediately and enjoy!
**Make ahead tip:**
You can make the crêpes up to 2 days ahead. Just wrap them well and store in the refrigerator. Make sure to bring them to room temperature before proceeding with the sauce.