Prepare a 9×13-inch pan by spraying it with butter-flavored cooking spray. Set aside.
Cut the pound cake into small, bite-sized cubes. Spread them onto a baking sheet and let them dry out slightly for about 20 to 30 minutes while you prepare the treats. This helps prevent the cake from becoming too soft in the mixture.
In a large pot over low heat, melt the butter. Stir in the sweetened condensed milk until smooth and warmed through.
Add 14 ounces of the mini marshmallows and stir until mostly melted and creamy.
Remove the pot from the heat and stir in the vanilla extract and crushed freeze-dried strawberries.
Fold in the Rice Krispies cereal until evenly coated.
Let the mixture cool for about 1 minute, then gently fold in the remaining 2 ounces of mini marshmallows along with the pound cake cubes. Try not to overmix so the cake pieces stay intact.
Transfer the mixture to the prepared pan and gently press into an even layer. Do not pack the treats down firmly.
Let cool completely before slicing into squares.