1.) Place all ingredients, EXCEPT for the vinegar, into a medium saucepan and whisk until smooth. Cook the mixture, over medium heat, for 30-45 minutes, or until thickened into a paste; stir often during this process.

2.) Whisk the vinegar into the thickened paste, and cook for another 10-15 minutes.

3.) Let the mustard cool to room temperature and place in the frig for storage, or use it right away. The mustard can be safely stored for several months.