Preheat oven to 350℉. Grease a 9x13-inch glass baking dish with butter or non-stick cooking spray. Set aside.
On a large sheet of wax or parchment paper, spray 4 marshmallows with blue food dye spray.
On a separate sheet of wax or parchment paper, spray 8 marshmallows with red food dye spray.
Arrange the chocolate chips in an even layer in the bottom of the prepared baking dish.
Place the four blue marshmallows over the chocolate, in the upper left corner of the pan. Place four red marshmallows next to the blue, finishing the first row.
To the second row, add 4 white marshmallows, place 5 red marshmallows in third row, and finally, 5 white marshmallows in the bottom row.
Take the two remaining marshmallows and cut them to fit the four spaces at the end of each line. The two pieces that finish the red rows will need to be sprayed with the red food dye before being placed into position.
Bake in preheated oven for 10 minutes. Serve immediately with graham cracker sticks.
Notes
For a more patriotic look, sprinkle some coarse sugar over the blue marshmallows while they're warm. This adds a sparkle to the star portion of the flag.
If desired, spray the marshmallows after baking. You can attempt to free hand spray the marshmallows when they are warm out of the oven. This will allow them to be a bit softer, but the color won't be as vibrant.
If the chocolate starts to harden and becomes difficult to dip into, you can place the dip back in the oven for a couple of minutes. Alternatively, you can scoop out portions and reheat them in the microwave for a few seconds at a time.