Boil the eggs until cooked through but still a little soft in the center.
4 Eggs
Melt the butter in a saucepan, then add the flour and stir.
30 g Butter, 1 tbsp Flour
Let it "sweat" a little, then add a little bit of milk and stir it in until it's smooth. Repeat and add the milk little by little, stirring rigerously to avoid lumps.
500 ml Milk
Take the sauce from the stove and add the mustard. Add salt, pepper (if needed), and season with honey or sugar and lemon juice to your taste.
5 tbsp Mustard, some Salt, some Pepper, some Lemon Juice or Vinegar, some Sugar or Honey