Preheat the oven to 350 °F and line an average cupcake pan with white cupcake liners. Or use mini cupcake pans (you'll need at least two 24-cavity pans)
In a large mixing bowl, add the cake mixes, eggs, milk, sour cream, flour and oil. Mix well using a hand mixer, or by hand. Remove as many lumps as possible.
Fill each cupcake liner about half full. This was about ¼ cup each. You don’t want them to puff up too much past the liner top as it makes it harder to decorate them.
Bake for 15 minutes or until a toothpick comes out clean. Move to a wire rack to fully cool.
Using a cake board or wire rack covered in parchment paper, position your cooled cupcakes in 5 lines of 7 (35 cupcakes total). Push them right up against each other so they’re nice and snug.
Place 1 ½ containers of the white frosting in a medium mixing bowl and red gel food coloring. Be sure to use “Super Red” or “Red Red” and you’ll need about 1 teaspoon. Note, it won’t look as red as you want it, but once it settles and you get it on the cupcakes, the red really pops.
Place one container of frosting in another mixing bowl and add about ⅓ of the tube of blue gel food dye (if you use the same kind I do, see notes below). You can also add a bit at a time and mix it in until it reaches a rich blue. Be sure to mix until no white or blue streaks appear.
Place the blue frosting in a frosting bag and use an Ateco #826 frosting tip or a Wilton 1M to pipe the frosting onto the top first three cupcakes of the first two lines. This will be 6 cupcakes total. Start at the top and outside edge of the cupcake, move in a counterclockwise motion, with fluid movement, keep moving your hand in a circle until you reach the middle. Ever so lightly, boink the tip down just a bit and bring it back up so it leaves a mini spike in the middle of the cupcake.
Sprinkle the white sugar pearls over the blue cupcakes only.
Repeat the frosting process for the red frosting and finish out the top first line, do the third full row of cupcakes, and the last entire row of cupcakes.
Decorate the remaining cupcakes with the leftover white frosting. Enjoy!