In a seal-able container, add Rauchbier, mustard seeds and malt vinegar. Mix to combine. Seal and let sit 4 hours to overnight.
In a sauté pan over medium heat, add oil and onions. Stir occasionally until the onions are golden brown, about 10 minutes. Add garlic and cook for another 2 minutes. Transfer to a blender, also adding beer-mustard mixture, brown sugar, mustard powder, salt and pepper. Blend until smooth, about 2 – 3 minutes.
Transfer the finished beer mustard to a sterile jar and refrigerate. This mustard will last a very long time.
Ways to Use Rauchbier Onion Mustard:
Try adding mustard to a vinaigrette
Spread over a cut of beef | pork | chicken and roast 375˚F | 191°C oven