COMMUNITY SERVICE ANNOUNCEMENT:

Dijonnaise is not, I repeat, not a viable DIY proposition. Seriously. If you ever find yourself halfway through the construction of a delectable sandwich, only to look in the fridge to find you've run out of your beloved Maille brand, do not fool yourself into thinking that you are some kind of condiment-based chemist. Do not do as I did, and go "Aha!" and pick up a jar of Dijon seeded mustard in one hand, and a jar of mayonnaise in the other and go, "Dijon, meet Naise". And then make the jars kiss. It's just. Yuk. Best left to the professionals. Take heed.