Create a double boiler by placing a small saucepan with water on the stove and heat to a low boil.
Whisk together the eggs, sugar, and key lime juice in a shatterproof glass bowl.
Place the bowl over the simmering water making sure it fits tightly and no steam will leave. Constantly stir the mixture until it reaches 180 degrees and it thickens.
Remove the bowl from the heat. Stir in the butter until it has reached a smooth consistency.
On a baking tray, spoon in the mixture into the mini graham cracker crusts then refrigerate until it has cooled.
Using a plastic bag with the corner cut off, pipe your whipped topping onto each one.
Garnish with a key lime slice, raspberry and mint leaves before serving!