1) Add milk and eggs to blender and combine. Add the flour 1/2 a cup at a time, blending after each addition to ensure there are no lumps. Add pinch of salt and melted butter then blend for 30 seconds until you achieve a smooth, silky consistency. Set aside in refrigerator for at least 30 minutes to rest. While it rests make the orange butter sauce.
2) Dip a piece of kitchen paper in butter and grease a small frying pan. Ladle a spoonful of batter into the pan. With a flick of the wrist swivel the pan in order to get a nice even covering all over. A good crepe should be paper- thin. Cook on a high heat and flip it over when you see the edge turning golden brown. Remove crepes from pan and fold in half and press into a muffin tray to form little cup shapes. Bake in hot oven for 10 to 12 minutes until slightly crispy and brown around the edges, the middle should remain spongy and light.
3) Combine the butter, sugar, citrus juices, and zest to a small saucepan and cook for about 10 minutes until it caramelizes. It should be a golden color. Remove from heat, add the Grand Marnier, return to the heat and continue to whisk and reduce until syrupy-about 10 minutes. When done, set to the side.
4) To assemble, place crepe cup in the center of plate and place a scoop of vanilla ice cream in the cup. Drizzle with the orange butter sauce.