Bring the milk to a boil in a saucepan with the butter and salt.

Add the flour and stir mixture for 4-5 minutes on low heat until it leaves the sides of the saucepan. IMPORTANT that you keep stirring throughout.

Leave to cool (MUST be cool enough so that eggs do not curdle when added), then fold the eggs in individually with a wooden spatula.

Cut the cheese into small cubes (about 1/4 in) and work evenly into the mixture. Form little balls with a spoon and place on a greased baking sheet.

Preheat the oven to 340F. Separate the egg yolks from the whites. Brush the little balls with egg yolk and sprinkle with grated cheese. Bake for 20-25 minutes.