Mustard Butter, Live

• 1 cup heavy cream, organic preferred
• 1 teaspoon dijon mustard
• 1/2-3/4 teaspoons ground mustard seed, to taste
• 1/2-1 tablespoons black sesame seeds
• sprinkle of tumeric for color and more bitter flavor
• 1/2 teaspoon ground cumin, optional, to taste
• 1/4 cup finely minced herbs/vegetable/fruit, such as white scallion, lime leaf basil, cilantro, pea pod tendrils, mustard greens
• 1 teaspoon finely chopped anchovy, optional, to taste
• 1 tablespoon mirin, rice wine vinegar, cider vinegar or even lime or lemon juice
• pinch of kosher salt
• a few drops of fish sauce, tamari or other flavoring, optional

1. In a blender process the cream until it turns to a soft butter. You can pour off the excess liquid, the buttermilk, (which you can use for something else) and then mash the drained butter with a fork or potato masher. Or see the mixer method clearly illustrated, step by step, in the link to my comment below from "cooking for engineers."
2. Add the mustard, mustard seed, any other spice you may want for variation, and sesame to the butter. Incorporate as much liquid as you can by whisking it in. Chill for an hour before continuing if that is a problem for you.
3. To your finely minced fresh herbs/vegetables/fruit, add the mirin, vinegar, or citrus juice, other flavorings, and salt. Toss and let sit for 10 minutes. Drain excess liquid. Can you eliminate this step? Yes, but this dressing enhances the add-ins, if you have the time. Add the optional chopped/finely minced anchovy.
4. Mix in your "dressed" or "undressed" concoction to the butter. An another alternative is to process these together in a blender, if you want more of a final pureed vs. rustic style. Sometimes I do a combination of the two.
5. Dab or slather this on your torpedo roll or scoop it upon a grilled steak (beef or fish).

heavy cream, mustard, ground mustard, black sesame seeds, tumeric, ground cumin, herbsvegetablefruit, anchovy, mirin, kosher salt, fish sauce

Taken from food52.com/recipes/6390-mustard-butter-live (may not work)