Combine the first 5 ingredients in a bowl, mix well.
Whisk in vegetable oil and mix until the mixture is smooth and the lumps are gone. May be prepared in advance and stored in an airtight container in the refrigerator for several weeks.
If a recipe calls for a box of Jiffy Corn Muffin Mix, simply add the above mixed ingredients to that recipe in lieu of the mix.
To make Corn Muffins, preheat the oven to 375 degrees F, and grease 6 cups of a standard-size muffin tin.
Combine mix with egg, milk and creamed corn and any other optional mix-ins, being careful not to over mix. Allow the batter to rest for 2-3 minutes. You will see the batter becomes light and fluffy.
Scoop the batter into the greased muffin cups, distributing evenly. For light and tender muffins, take care not to overwork and “deflate” the batter. Bake for 11-14 minutes, plus or minus a minute or two, depending on use of optional ingredients and typical oven variances. You want the muffins to be just cooked through the center. Cool in the pan for 5 minutes, and then remove to a rack.
The muffins are moistest the day of baking, but I use an easy trick to freshen any leftovers: Once cool, wrap any leftovers and refrigerate. When ready to eat, place on a plate and wrap in a damp paper towel. Reheat very gently for moist, almost new muffins.