My sister made this for some holiday meals before coming here on Christmas Day. She could not remember the 4th ingredient so I searched on the internet and found it. She made a batch here and we put it in little jelly jars so we could send some home with the other guests. This is very good with pretzels for dipping. Also good on ham or pork. I eat it on a lot of sandwiches.
8 oz prepared mustard (we used Dijon)
14-oz can sweetened condensed milk
2 Tbsp horseradish
2 Tbsp Worcestershire sauce
Mix all together and store in refrigerator. Use within 3 months.