Whisk and mix the ingredients in a 5- to 6-quart lidded container. Finish by picking up the container and vigorously shaking until the flours are completely blended.

The ingredients must be very well mixed, otherwise, the xanthan gum will not be evenly distributed and your baked or fried goods will be inconsistent.

** Do not substitute with potato flour.

*** Psyllium can be used as a substitute for xanthan gum only if the dough is to be used in recipes that are baked in a loaf pan. Psyllium causes the dough to become crumbly after refrigeration.

If you’re measuring using U.S. cup-measures, be sure to pack the flour tightly into the cup, as if you were measuring brown sugar.

Whisk together the flour, cornstarch, xanthan gum, yeast & salt in the bowl of a stand mixer, or in any 5-quart bowl or lidded container.

Add the milk, eggs, honey, melted butter & vanilla. Mix with a wooden spoon or a heavy-duty stand mixer fitted with the paddle attachment (preferred method).

Cover (not airtight) and allow to rest at room temperature until the dough rises, approximately 2 hours.

The dough can be used as soon as it's thoroughly chilled. Refrigerate it in a lidded (not airtight) container and use over the next 5 days. Or freeze for up to 3 weeks in 1-pound portions and thaw in the refrigerator overnight before use.

On baking day, choose your pan. Brioche can be made in a 7-inch fluted brioche tin or an 8 ½ x 4 ½-inch loaf pan. Prepare the pan with butter. Using wet hands, pull off a 1 ½-pound (large grapefruit-size) piece of dough and drop it into the prepared pan. Smooth the top with water.

Cover with plastic wrap or a roomy overturned bowl and let rest for 60 minutes.

Fifteen minutes before baking, preheat the oven to 350°F.

Brush the top of the loaf with egg wash and bake until golden and firm, 40 to 50 minutes.

Allow to cool on a rack before eating.