HOW DOES COOKING THICKEN THE MIXTURE?
During cooking, the egg yolks will coagulate and the starch grains in the cornflour will absorb water then gelatinise, thickening the mixture.
MAKES 800 G
100 g egg yolk (about 6–8 eggs)
120 g sugar
50 g cornflour
500 g full-cream milk
50 g butter, cut into cubes
1 Line a baking tray with plastic wrap. Blanch the egg yolk with the sugar, then whisk in the cornflour.
2 Bring the milk to the boil in a saucepan. When it starts to bubble, pour half into the yolk, sugar and cornflour mixture, whisking constantly.
3 Pour the whole mixture back into the saucepan with the remaining milk and cook over a high heat, whisking constantly to prevent it sticking to the bottom.
4 When the mixture begins to thicken, let it cook over a high heat for 1–2 minutes more. Remove from the heat and whisk in the butter.
5 Pour into the prepared baking tray and immediately cover with plastic wrap (with the plastic touching the surface). Set aside in the refrigerator.