Place the freeze-dried strawberries in a food processor and blend until they form a fine powder.

Combine the strawberry powder and powdered sugar in a medium bowl and whisk until the mixture is evenly pink.

Pour the strawberry-sugar mixture into a 1-gallon freezer bag and seal, then shake gently to break up any clumps.

Add the white chocolate chips to a microwave-safe bowl and microwave in 30-second intervals, stirring after each, until completely melted and smooth.

Place the Chex cereal in a large mixing bowl, pour the melted white chocolate over the cereal, and gently fold with a spatula until all pieces are evenly coated without crushing them.

Transfer the coated cereal to the prepared freezer bag, seal the bag, and gently shake and turn it until all the cereal is coated with the strawberry-sugar mixture.

Spread the coated cereal in a single layer on a baking sheet and refrigerate for 15 minutes, or until the chocolate is set and the pieces feel dry to the touch.

Break up any large clusters with your hands, transfer the puppy chow to an airtight container, and store at room temperature until ready to serve.