Ground yellow mustard seed, also called mustard flour, is the type of mustard seed used in the traditional topping for ballpark franks. It’s easy to prepare, too. Simply mix equal parts mustard, flour, and water to make basic mustard. Beyond that, the potential flavor combinations are only as limited as your imagination. Try substituting various cooking wines or specialty vinegars for water. Red wine vinegar complements the light mustard taste of the yellow seeds. Adding turmeric or even exotic saffron will have the foodie in your circle begging for your secret recipe for homemade mustard! If you’re looking for spicier mustard, add horseradish or mix with black mustard seeds for truly unique tastes. Yellow mustard powder, pre-roasted and ground from fresh mustard seeds, takes the work out of preparing mustard seeds from scratch to mix into your own mustard.