Makes 1¼ cups
Preparation time: 10 minutes, plus one to two days sitting
- ½ cup water
- 1 cup crushed brown mustard seeds or ¾ cup whole brown mustard seeds, finely ground
- ½ cup red-wine vinegar
- 1 tsp. coarse sea salt or kosher salt
- 1⁄8 tsp. ground cinnamon
- 1⁄8 tsp. ground cloves
- 1⁄8 tsp. ground nutmeg
- 1⁄8 tsp. ground allspice
- ¼ tsp. black pepper (optional)
Mix all the ingredients in a nonreactive glass or ceramic mixing bowl.
Cover with plastic wrap and let sit at room temperature for one to two days so that the mustard begins to mellow and the flavors meld. (If you find that the final mustard still seems slightly watery after sitting at room temperature for one or two days, pour it into a blender or food processor and process until smooth.)
Transfer to an airtight container.
Cover and refrigerate overnight; store in the refrigerator for up to six months.