Hard-boil or semi hard-boil eggs with your preferred way of cooking eggs.
In the meantime, melt butter in a medium-sized saucepan.
Add flour and a pinch of sugar and mix well.
Stir constantly for about 5 to 7 minutes until the butter-flour mixture lightly browns.
Add chicken broth and milk and cook on medium heat until sauce thickens. Make sure to stir constantly to avoid burning the sauce.
Remove pan from the heat. Add heavy cream, salt and pepper and mustard and mix until everything is well combined.
Peel eggs. Place them either whole or halved the eggs into the sauce to reheat them. In case the eggs are still warm you can just ladle some sauce over them.