In a clean, dry quart-size mason jar add the dry ingredients in the order listed (flour, salt, baking powder, cinnamon, sugar, cranberries, nuts) using a large funnel and tapping the jar on the counter between each layer to settle.
Add lid to jar, print out direction tags and attach tag to the jar with ribbon or twine.
When Ready To Bake:
Preheat the oven to 400 degrees. Grease or line a 12-cup muffin tin.
Pour the muffin mix from the jar into a large bowl.
In a small bowl, combine the milk, butter and egg. Stir into the dry ingredients, just until no flour streaks remain.
Spoon evenly into muffin cups, about half full. If desired, sprinkle tops with a cinnamon-sugar mix.
Bake 14-16 minutes or until a toothpick comes out clean. Cool for about 5 minutes and then turn out onto a cooling rack.
One jar of muffin mix makes 12 regular size muffins.
Notes
The sealed muffin mix will stay fresh for 3-4 months.