How to Make an Egg Wash

These are 10x better than regular twice baked potaotes #potatoes The full recipe for Americans- 4 Russet potatoes weighing roughly 12 oz each 3/4 heavy cream reduced by 2/3 seasoned with salt and pepper 1 tsp rosemary salt or kosher salt 1 tsp fresh ground black pepper 3 oz unsalted butter 6 egg yolks (save 2 for the egg wash) 2 tsp finely sliced Italian parsley 2 tsp finely chopped Chives 2 reserved egg yolks 2 tsp milk for the egg wash 3 oz grated gruyere cheese or other cheese of choice (salt