Line a 9-by-9-inch pan with foil and spray with cooking spray.
Place the crackers and powdered sugar in a food processor or blender to pulverize. Alternatively, cracker-crushing can be done by hand by placing crackers into a large ziptop food storage bag, zipping it shut, and rolling over the bag with a large glass, coffee can, or rolling pin).
Place the cracker crumbs into a bowl, add the melted butter, and stir to combine.
Press a little less than 3/4 of the mixture into the bottom of the prepared pan, set the pan aside, and reserve the remaining 1/4 of the cracker crumbs.
In a large mixing bowl, combine pink lemonade concentrate, sweetened condensed milk, and stir until combined.
Add the Cool Whip and stir until smooth.
If desired, add food coloring drops to desired shade and stir until color is uniform.
Pour the mixture over the crust, noting that you may have an extra half cup or so of the mixture depending on the height of your pan; do not overfill the pan. Use the extra mixture for a mini-tartlette, as a dip for fruit, or just eat it.
Top with the reserved cracker crumbs by sprinkling evenly over the top.
Place pan into the freezer to set up for at least 4 hours before slicing and serving. Store extra dessert in the freezer with a sheet of foil over the top. It will keep for up to 3 months.