In a large mixing bowl, combine the flour and salt.
Whisk in the milk, eggs, and melted butter until smooth, creating the crêpe batter.
Preheat a nonstick skillet over medium heat and pour in a small amount of batter, swirling it to evenly coat the bottom.
Cook the crêpe for about 1-2 minutes on each side, until lightly golden, then repeat with remaining batter.
In another pan, prepare the sauce by melting butter, then adding orange juice, sugar, and orange zest. Let it simmer until slightly thickened.
Add the crêpes to the pan with the sauce, folding them into quarters.
Pour the Grand Marnier over the crêpes and carefully ignite with a long lighter to flambé. Allow the flame to subside.
Serve the Crêpes Suzette immediately, spooning sauce over each serving.