Custard Sauce for Apple Pie

• 1 Egg yolk
• 15 grams Sugar
• 80 ml Milk
• 1 less than 1 teaspoon Liqueur (Calvados)

1. Mix together the egg yolk and sugar in a bowl until it becomes white.
2. Put the milk in a pot and heat until it is just about to boil.
3. Pour half into the bowl from Step 1 and mix well.
4. Pour in the remaining milk and mix well.
5. Return the entire mixture to the pot.
6. Heat on medium heat while stirring until it is thick enough to draw a figure 8.
7. When it has thickened, remove from the heat and cool in an ice water bath.
8. Stir while cooling in the ice water bath.
9. When it has cooled, add the liqueur.
10. Top an apple pie with the sauce.
11. This is an apple pie recipe.
12. The filling doesn't contain any butter, so it goes really well with this sauce.

egg yolk, sugar, milk, liqueur

Taken from cookpad.com/us/recipes/145198-custard-sauce-for-apple-pie (may not work)