Meanwhile, make 2 batches of The BEST Cream Cheese Frosting
and fit 2 plastic piping bags with large decorating tips (or wash, dry, and re-use one bag). Draw one thin line of pink food coloring and one thin line of blue food coloring on either side of the plastic bag(s) (I put mine in the folds of the bag to make it easier) with a toothpick. Get as close to the tip as you can. (The food color lines will thicken after you insert the frosting.) Gently fill the bag(s) with frosting, being careful not to touch the food coloring with your spatula. Twist the end and squeeze until both colors are coming out the tip.