Melt the butter in the microwave for 30 seconds on full power

Then add the marshmallows to the melted butter and put it back in the microwave for 30 seconds on full power

After take it out the microwave and pour the melted butter with marshmallows and the cocoa pops cereal in a big bowl for all of it to fit and stir

Leave it to sit in a temperature room for 30 minutes

Cut them in to squares and then you have cocoa pops bars