To make the Hollandaise Sauce, first melt the butter in a saucepan and skim any white solids from the surface. Keep warm.
Put the egg yolks, vinegar, a pinch of salt and a splash of ice-cold water into a glass bowl that will fit over a saucepan. Whisk together for a few minutes then put the bowl over barely simmering water until thick (about 3-5 mins).
Remove from the heat and slowly whisk in the melted butter, whisking continuously until thick, season with lemon juice and paprika.
Toast the muffins, then top with grated Mature Cheddar and pop under the grill to melt.
Top with the smoked ham, a poached egg and a spoonful of Hollandaise, and garnish with a sprig of parsley.