Place a jumbo silicone muffin pan on a baking sheet. Blitz the shortbread cookies in a food processor until they’re fine crumbs, or crush them in a plastic bag with a rolling pin until they’re finely crumbled. Mix them in a bowl with the melted butter.
Divide the shortbread crumbs between the 6 cavities in the muffin pan, and press them firmly into the bottom of the pan to form your cheesecake crust.
Place the cold water in a small bowl, and sprinkle the gelatin on top. Whisk them together, then let the bowl sit for 5 minutes so the gelatin can hydrate and absorb the water. Once it feels very firm, microwave it for 10-15 seconds, until fully melted and liquid.
Put the cream cheese in the bowl of a large stand mixer fitted with a paddle attachment, and beat it until it is smooth, creamy, and free of lumps. (A hand mixer can also be used.) Add the sugar, lemon juice, vanilla bean paste, and salt, and mix well, scraping the bottom and sides of the bowl occasionally.
With the mixer running on low speed, gradually add the cream and creamer, mixing until everything is smooth and well-combined. Finally, add the liquid gelatin and mix it in. Finish mixing by hand, scraping the sides and bottom well.
Divide the cheesecake into 4 portions (each should be about 7 oz, if you want to measure them out.) Stir a drop of gel food coloring into each one and mixing until the color is smooth and uniform.
Take your first color and divide it between the 6 cavities—I found it was fastest and easiest to use a cookie scoop, but you could use a regular spoon, or even pipe the cheesecake in if you want to be really precise. Spread it into a smooth layer with the back of a spoon, then add a second color on top of the first.
Continue to layer the cheesecake colors until all 4 of them have been added to the pan. Smooth the tops of the cheesecakes, then place them in the freezer for at least 2 hours to firm up. (The exact time will depend on the temperature of your freezer.) They should feel solid to the touch before you try to unmold them.
To unmold, simply press from the bottom of one of the cavities and turn it upside-down, pushing the cheesecake out into your hand. Let them sit at room temperature for 30 minutes to defrost before serving. They can also be refrigerated for several days after being unmolded, if you want to make them in advance. These cheesecakes should be stored in the refrigerator and served chilled.
To decorate, top each cheesecake with a swirl of whipped cream, a pinch of sprinkles, and a few candy eggs.