Spread the sprinkles or colored sugar out in an even layer on a plate. Here, I'm using red, white and blue sprinkles, but you can also use a single color of sprinkles or colored sugar, perhaps red for some of the cupcakes, blue for others and white sugar pearls or a sparkly clear colored sugar for the rest of your 4th of July cupcakes.
Gently roll the edges of the cupcakes in the sprinkles or colored sugar, pressing down to make sure the sprinkles adhere to the cupcakes. Insert the flags or colored stars into the center of the 4th of July cupcakes.
