Mornay Sauce

Ingredients

• 600 ml milk
• 50 g butter
• 50 g plain flour
• 100 g Gruyere, grated
• 40 g Parmesan, grated
• 1 pieces egg yolk
• 0.25 pieces onion
• 2 pieces cloves
• 1 pieces bay leaf
• 0.25 tsp nutmeg, grated

Steps

1. 1
   Infuse the milk with the onion studded with cloves and the bay leaf: bring to just below a simmer, take off the heat and leave 20 minutes. Strain.
2. 2
   Melt the butter, stir in the flour and cook 3 minutes without colouring.
3. 3
   Whisk in the infused milk gradually until smooth, then simmer 10 minutes, whisking often, until it coats a spoon.
4. 4
   Season with salt, pepper and nutmeg.
5. 5
   Take the pan off the heat before adding the cheeses — boiling cheese in a sauce makes it stringy and greasy. Stir until melted.
6. 6
   Beat a little of the warm sauce into the egg yolk, then stir it back into the pan off the heat.
7. 7
   Use immediately, or press cling film to the surface to stop a skin forming.