Pre-heat oven to 350 degrees. Line a muffin tin with cupcake wrappers.
Melt butter.
Stir together Graham cracker crumbs, sugar, and melted butter.
Scoop 1 heaping tablespoon crumb mixture into each cupcake wrapper. Pack down crumb mixture into bottom of cupcake wrapper using your hands or the back of a spoon.
Bake for 12 minutes. Remove from the oven and allow to cool completely.
For the Filling
If using a stand mixer, attach paddle attachment. Mix together sweetened condensed milk, egg yolks, key lime juice, lime zest, and drop of food coloring.
Spoon on top of the crusts. Fill the cupcake wrappers 3/4 of the way full.
Bake at 350 degrees for 10 minutes.
Remove from oven, allow to stand for 10 minutes.
Refrigerate a few hours or overnight.
For the Whipped Cream
With your stand mixer fitted with the whisk attachment, beat heavy cream until foamy and it starts to thicken.
Add in vanilla extract.
Slowly mix in powdered sugar. Continue beating until soft peaks form.
Notes
*Filling recipe adapted from Nellie's Key Lime Juice