- To make the roux for the béchamel sauce, melt a tablespoon of Cadí butter PDO in a saucepan, add two tablespoons of flour, turn down the heat and leave to cook for ten minutes.
- Place the sprig of rosemary in another saucepan and add 150 g of mineral water. When it begins to boil, turn off the heat, cover the pan and leave it to infuse.
- In a metal bowl, place three egg whites and a pinch of salt and whisk to soft peak stage.
- In another bowl, place the four egg yolks with a half a glass of dry white wine. Add a pinch of salt and beat using an electric mixer.
- Grate 125 g of Urgèlia cheese PDO.
- In a pan, place 200 ml of milk, the rosemary infusion (sprig removed) and almost all the grated cheese. Leave over a low heat to melt and combine.
- When the cheese has melted, add the roux (made at the beginning) and the nutmeg. Stir constantly and pour into another pan. Cover with cling film to prevent a skin from forming.
- Once the béchamel is lukewarm, gradually add the egg yolks and then fold in the whisked whites. Ladle the mixture into four ovenproof serving bowls and sprinkle the remaining cheese on top.
- Place the bowls in the bottom of the oven and bake at 180 ºC for 20-25 minutes.
Garnish with some thyme leaves and serve immediately.