Spray a 9×13-inch pan with butter cooking spray and set it aside.
Place the freeze-dried strawberries in a food processor and blend until they become a powder. Set it aside.
In a large pot over medium heat, melt the butter and add the salt. Use a rubber spatula to spread some butter up the sides of the pot to help prevent sticking.
Pour in the sweetened condensed milk and stir to mix it with the butter.
Add the mini marshmallows and stir continuously over medium heat until they are fully melted. Then, remove the pot from the heat.
Stir in the vanilla and the freeze-dried strawberry powder until everything is well combined.
Pour in the Rice Krispy cereal and use the rubber spatula to gently fold everything together until the cereal is evenly coated.
Pour the mixture into the prepared pan. Wet your hands, shake off the excess water, and gently press the mixture into the pan. Don’t press too hard, or the treats will turn out too dense!
Leave the treats at room temperature for about an hour to cool and firm up.
Using a rubber spatula, remove the treats from the pan and then cut them into squares with a knife. Enjoy!