01 - Divide the shredded cheeses into five separate small bowls. Add a few drops of different food colorings to each bowl and mix thoroughly until the cheese is uniformly colored.
02 - Lay out the slices of rainbow bread. Evenly spread softened butter on one side of each slice.
03 - On two bread slices, with the unbuttered side facing upward, arrange the distinctly colored shredded cheeses in prominent stripes, alternating the colors to create a vibrant, funky visual.
04 - Place the remaining bread slices on top of the cheese layers, ensuring the buttered sides are facing outward.
05 - Heat a nonstick skillet or frying pan over medium-low heat. Carefully place the assembled sandwiches into the heated skillet. Cook for approximately 3 to 4 minutes per side, applying gentle pressure with a spatula, until the exterior of the bread achieves a golden-brown crispness and the cheese is thoroughly melted.
06 - Remove the grilled cheese sandwiches from the pan. Slice them diagonally to showcase the colorful cheese interior and serve immediately for optimal enjoyment.