Is best when fresh made. Take good flour of mustard; put it in a
plate, add to it a little salt, and mix it by degrees with boiling
water to the usual consistence, rubbing it for a long time with a
broad-bladed knife or a wooden spoon. It should be perfectly
smooth. The less that is made at a time the better it will be. If
you wish it very mild, use sugar instead of salt, and boiling milk
instead of water.