Peel and boil potatoes in salted water for about 20 minutes until tender
Boil eggs for 7–8 minutes, then cool and peel
Melt butter, stir in flour and cook briefly without browning
Slowly whisk in milk and broth until smooth
Simmer until creamy
Add mustard, sugar, lemon juice, salt, and pepper to the sauce
Adjust seasoning to taste — it should be creamy, slightly tangy, not too sharp
Add eggs to the sauce or pour sauce over them
Serve with potatoes
