Lightly crush/break up the mustard seeds using a spice grinder or blender.

There should still be chunks of mustard seeds.

Add in the other dry ingredients and mix.

Add in the vinegar. Dry white wine can be used in place of up to half the total vinegar.

Cover the bowl with plastic wrap and leave at room temperature for 24 - 48 hours for the mustard seeds to absorb the liquid and the flavours to combine.

You can at this point either leave the mustard as is, or blend into a smoother consistency.

Spoon into jars and put into the fridge.