1. In top of a double boiler, add mustard and vinegar; stir well.
2. Cover and allow it to stand for 8 hours or overnight.
3. Add sugar, eggs and salt; mix well.
4. Keep over boiling water and cook 3 to 5 minutes, stir constantly until thickened.
5. Serve as an accompaniment to your main dish or store in airtight containers in refrigerator.