I'm using the Ball recipe for Dijon, as it is a gold standard for canning safety. If you are making mustard for immediate use, I suggest a non-canning recipe. This is going to be crazy intense the day it's made. Canning recipes require a decent amount of time on the shelf to mellow. I figure this will be ready to use in about a month, after Passover. Stupid no-mustard Passover kitnyot rule. That's why horseradish is such a big thing for that week.
I made this with two slight deviations from the original recipe that do not affect the safety, and are actually common in other canning recipes I've made. The first was using dried rosemary instead of fresh, because that's what I had. The other change was letting the wine mixture sit for about ten minutes after simmering before straining. I just wanted to infuse it a little extra, and make sure it was cool enough not to crack the room-temperature jar. Oh yeah, and I used Chardonnay, because that's the white wine that was open from previous recipes. It was 1/4 C short, so I used vinegar to make up the volume. You can always add more acid to a water-bath recipe, but not less.
*2 C chopped onion
*2 C Pinot Grigio or other dry white wine
1 C white wine vinegar (at least 5% acidity)
1 tsp kosher or canning salt
*6 cloves garlic, chopped
4 peppercorns
*1 sprig fresh rosemary or 1 tsp dried
*1 C yellow mustard seeds
1/3 C dry mustard
up to 2-2/3 C water, if needed
4. Transfer mixture to a saucepan. Bring to a boil, stirring often to prevent scorching. Reduce heat and simmer 5 minutes, stirring often, until desired consistency.
5. Ladle hot mustard into hot jars to 1/4-inch headspace. De-bubble, wipe rims, and apply lids and rings. Process in boiling bath canner 10 minutes. Turn off heat, remove lid, and let jars sit 5 minutes before removing. Mustard likes to siphon, and four of mine did despite following the directions. Cool, test seals, clean jars, and store. Any unsealed jars should be refrigerated or frozen.Makes 3+ cups, depending on consistency
Difficulty rating :)