Preheat oven to 350 degree F. Generously coat 14 muffin cups with non-stick cooking spray.

Prepare cake mix with water, oil, and eggs, according to package directions. Divide batter between prepared muffin cups, filling nearly to the top. Bake for 17 to 19 minutes, or until a toothpick inserted in the center of a cupcake comes out clean. Remove from oven and allow cupcakes to cool completely in pans.

When cupcakes have completely cooled, prepare the frosting. Use a mixer to mix the Pillsbury frosting with 4 ounces cream cheese until thoroughly combined and creamy.

Remove cooled cupcakes from cupcake pan and use a serrated knife to cut them in half so you have 14 cupcake tops and 14 bottoms.

To assemble mason jar cupcakes, place a cupcake bottom in the bottom of a mason jar. Use a pastry bag with decorative tip (I used such and such tip) and pipe on some of the frosting. Decorate with a few M&M's or patriotic sprinkles, if desired, then add a cupcake top (top down).  Pipe frosting on top and decorate with additional M&M's and/or patriotic sprinkles, as desired.

Decorate with additional patriotic decorations like the flag and star picks pictured. For a portable dessert, place the lids on the jars, pack up some plastic spoons, and take them with you!