Mustard flour is finely ground mustard seeds. It is used in mayonnaise and salad dressings. It also can be used for a "mustard plaster" to relieve respiratory distress.
A glutton free flour that is used in incredients for things such as mayonaise or honey mustard, particularly for products sold to people with allergies to wheat.
Mustard flour is basically mustard seeds ground up into a powder. You use it to spice up dishes or create your own sauces. Mustard flour is a great thing to have in the kitchen.
Mustard flour is simply the ground up seeds of the mustard plant. It is primarily used to make mustard when it should be smooth and not contain the seeds.