Preheat oven to 325 degrees.
In a mixing bowl, add in the graham cracker crumbs, sugar, and butter. Stir until the melted butter coats the crumbs.
Firmly press the crust into the bottom of a 9.5 inch spring form pan.
Place into the oven and bake for 15 minutes. Remove from the oven and let cool.
In a large mixing bowl, add in the cream cheese,
Beat the cream cheese with a hand mixer until smooth. This will help prevent lumps.
Add the granulated sugar in with the cream cheese. Beat on medium until combined. Scrape down the sides of the bowl and beat until any lumps of cream cheese are incorporated.
Add in the vanilla extract and the eggs one at a time. Mix each egg completely before adding the next and scrape down the bowl after each addition of egg.
Add in the sour cream and heavy cream. Mix until incorporated. Scrape down the sides of the bowl and beat any remaining bits.
Divide the batter into 6 bowls. I used an ice cream scoop and scooped it out equally. I got 3 scoops for each bowl.
Add each gel paste food color into a bowl with batter in it.
Thoroughly mix the gel food color into the each bowl of batter.
Just before adding the cheesecake mixture, line the outside of the spring form pan with heavy duty tin foil. I double wrap it to prevent the water from leaking in.
Starting with the red, add the mixture into the center of the cheesecake. Then add the orange to the center of the cheesecake. Repeat adding the yellow, green, blue, and purple to the center of the cheesecake.
Give the cheesecake a few taps to even out the top and remove any air bubbles.
Place the spring form pan in a slightly larger baking pan. Fill the outer pan with water. Fill it so it at least goes a quarter of the way up the spring form pan. This will keep the cheesecake from cracking.
Place in the oven at 325 degrees and let bake for 1 hour and 20 minutes or until done. To make sure the cheesecake is done, give it a wiggle. If it slightly jiggles in JUST the middle like jello, then it's done. If it jiggles all over, it needs to bake longer. Turn off the heat and crack the oven door slightly. Let it cool in the oven for an hour or two. I kept mine in the oven for about 2 and half hours and then placed it in the fridge.
Cut and serve!