Stir together all of the dry ingredients in a medium mixing bowl.
Transfer the mixture to a pint jar and cap tightly. Write the baking instructions on a tag and attach to the jar. Store at room temperature for up to a couple of months or freeze for up to a year.
To Make The Muffins
Preheat the oven to 400℉ and grease 6 muffin wells or line them with paper liners.
In a medium mixing bowl, stir together the contents of the jar, 2 Tablespoons vegetable oil, 1 large egg, and ⅓ cup milk until combined.
Scoop batter into prepared muffin wells. They should be about ⅔ full.