1/4 cup yellow mustard seeds
2 1/2 tablespoons black or brown mustard seeds
1/4 cup dry mustard powder
1/2 cup water
1 1/2 cups cider vinegar (if you like it less vinegary, reduce vinegar and increase water)
1 small onion, coarsely chopped
2 tablespoons firmly packed brown sugar
1 teaspoon salt
2 cloves garlic, minced or pressed
1/2 teaspoon ground cinnamon
1/4 teaspoon ground allspice
1/4 teaspoon dried tarragon
1/8 teaspoon ground turmeric
In a medium bowl, combine the mustard seed and dry mustard.
In a 1- to 2-quart stainless steel or nonreactive saucepan, combine the rest of the ingredients. Simmer, uncovered, over medium heat until the mixture is reduced by half, which will take 10 to 15 minutes.
Pour the mixture into the bowl with the mustard seed. Let it stand, covered, at room temperature for 24 hours. You may have to add more vinegar to keep enough liquid in the mixture in order to adequately cover the seeds.
Process the mixture in a blender or food processor until it is blended to the texture you like; this can take at least 3 or 4 minutes. You can leave it with some whole seeds remaining, or make a smoother paste.
Scrape mustard into clean, dry jars. Cover them tightly and place in the refrigerator for at least three days to allow the flavors to meld. (The mixture will continue to thicken. If it gets too thick after a few days, stir in additional vinegar or water.)
Enjoy.
If you want a smooth mustard texture (similar to Dijon), break down the whole mustard seeds prior to adding them to the mixture. Grind the whole mustard seeds in a spice or coffee grinder for a few minutes. They can also be broken down by hand with a mortar and pestle.
The salt and vinegar keep the mustard intact longer. Without them, it will more quickly lose its flavor.
There are three types of mustard seeds: yellow, brown, and black. The yellow mustard is milder and not as zingy as brown and black seeds. For reference, yellow mustard seed is what's in American yellow mustard, brown mustard seeds are used in most better mustards, and black seeds are commonly featured in hot mustards.