In a medium-size mixing bowl, whisk together the flour, milk, egg, and salt. Heat a large frying pan or wok over medium-high heat. When the pan is hot add a teaspoon of butter and swirl the pan to coat the surface of the pan with the melted butter. Pour 1/4 cup of the batter into the pan and tilt the pan with a circular motion so that the batter coats the surface in a smooth and even layer. After 2 minutes, lift up an edge of the crepe with a spatula to see if it is browning. When the underside has begun to brown, flip the crepe and cook the other side until it is also brown; about 30 seconds to 2 minutes. Repeat with the remaining 2 teaspoons butter and remaining batter.
In large 10-inch saute pan, melt 1/2 cup butter, granulated sugar, and orange zest together. Add 1 crepe at time and cover it with the orange butter. Fold each crepe in half, and then in half again, to make a triangle and place it on a warm plate. Repeat these steps to cook the remaining crepes. Pour the melted chocolate over the crepe and dust it with powdered sugar. Drizzle the Grand Marnier over it and light it at the table in front of the guest. Always use caution. Serve hot.