Whisk all ingredients together until well incorporated.
Store in an airtight jar for up to 6 months.
To Use: Whisk ½ cup mix with 2 ¾ cups of boiling water and 2 tablespoons of butter in a 9 x 13 baking dish. Add 3 cups of dehydrated potato slices (or use 3 cups parboiled sliced potatoes), pushing them down under the sauce. Cover and bake for 30 minutes at 350°. Uncover and bake for an additional 15 minutes. Let rest 5 minutes before serving.
