- First cook the ground meat in a large saucepan and set aside.
- Prepare hard-boiled eggs by cutting each egg into two halves lengthwise.
- Remove egg yolks into a bowl and mash them with a fork. Reserve the egg whites.
- Mix cooked beef, mustard, salt and pepper with the egg yolks until combined.
- Stir in sour cream moistening the mixture into a thick, paste-like consistency.
- Fill egg whites with egg yolk mixture, place the mixture through a pipping bag.
- Serve chilled.