1/3 cup Colman's dry mustard
1/3 cup cider vinegar 
2 teaspoons yellow mustard seeds
2 eggs
1/2 cup beer or water
2 tablespoons minced pickled jalape?s, plus
    2 tablespoons jalape? pickling liquid
1 1/2 tablespoons molasses
1 tablespoon minced onion
1/2 teaspoon salt

In a small bowl, mix the dry mustard and vinegar until a smooth paste forms. Stir in mustard seeds; cover, then let the mixture sit at room temperature for several hours.

Transfer the mustard mixture to a small, heavy saucepan. Add remaining ingredients and warm over medium-low heat. Cook the mixture slowly, stirring frequently, until thick, about 30 minutes.

Cool to room temperature. Transfer mustard to a small jar and refrigerate for later use. The mustard keeps for up to 2 weeks. Use it as you would any other mustard.