Grease your baking dish and set it aside.
In your large sauce pan, melt the butter over medium heat. When melted, add 15 oz. of marshmallows. Stir constantly until they start to melt.
½ Cup Butter, 20 Oz. Mini Marshmallows
Once the marshmallows are half melted, add in the peanut butter and vanilla extract, and keep stirring until it's all melted and mixed together.
¾ Cup Creamy Peanut Butter, 1 Tsp Vanilla Extract
Add the cereal and stir to mix. When it's about half mixed, add the last 5 oz. of marshmallows so you have some mostly-whole mixed in. Turn the heat to low or off entirely.
8 Cups Rice Krispies Cereal
Take half of the cereal mix and press it in an even layer on the bottom of your baking sheet.
Add the strawberry powder to the remaining half of the cereal, mixing it up to combine. It will probably be harder to mix since it has started cooling, so work quickly.
⅓ Cup Freeze-Dried Strawberries
Add the strawberry in a layer over top the peanut butter layer so you have a two-layer treat. Press it all flat and firm. Optional: Sprinkle some finishing salt across the top.
Finishing Salt
Let your cereal bars sit for at least an hour to cool and set. Then, cut and serve!