For the crust:
In the microwave, melt 5 tbs salted butter in a medium sized bowl. This should take about fifty seconds.
With a sharp knife, cut nine 1" x 1" squares of graham crackers for your garnish.
Pulse the remaining graham crackers in food processor until they are fine crumbs.
Add your graham cracker crumbs and 1 tbs sugar to your bowl of melted butter and stir to combine.
Spray an 8 x 8 baking pan with non-stick cooking spray.
Press the graham cracker mixture into the bottom of the pan to form the pie crust.
For the Key Lime Krispies:
Melt 3 tbs butter in a large saucepan.
Add 4 cups mini marshmallows and stir constantly until melted.
Remove from heat.
Add 3 tbs of the Lime Jell-o powder to your melted marshmallows and stir to combine.
Add 6 cups Rice Krispies cereal to the marshmallow mixture and stir until all the cereal is coated.
Turn that mixture onto your graham cracker crust and use a piece of wax paper to press the cereal mixture down firmly.
Once your treats have cooled completely, score the top so you have nine squares.
Top each square with a dollop of marshmallow creme, a fresh lime wedge and your reserved 1" x 1" graham cracker squares.