Butter the bottom of the pan.
Make the strawberry powder first. It is easiest to use a small food processor and add one bag of the strawberries and grind them until you have a powder. Set this aside.
For the other bag of strawberries, you want to make the pieces just a bit small so the bars will be easier to cut through. Open the bag, and then with the heel of your hand press down on the bag to smash the berries inside. You don't want them too small but just crunched up a bit.
This is optional, but you can add the cereal to a large mixing bowl and add the crunched-up berries and mix this together. Otherwise, you can just add the cereal and berries straight to the pot. You will do this later.
In a large saucepan or a medium-sized stockpot, add the butter and melt over medium-low heat.
Add the marshmallows and stir to coat with the butter, then add the strawberry powder. Stir this mixture of medium heat until the marshmallows are melted and creamy. Remove from the heat.
Pour the cereal and strawberries into the melted marshmallows and stir until the cereal is completely covered with the marshmallows.
Pour the mixture into the prepared pan. With a buttered spatula or your hand, press down the cereal to flatten the surface. Don't press down too much as that will make the bars hard
Let the bars sit at room temperature for about one hour to completely cool, then cut into bars.
If you want to add sprinkles to the treats I do that after I press the cereal in the pan while it is still a bit warm, but not hot This way the sprinkles will stick better.
Cover the bars with plastic wrap. They will keep for three days.