Get all of your supplies and ingredients together and ready to go.
Use butter or a non-stick cooking spray and grease up your spatula and pan.
Measure your 4 tbs of butter and 16 oz of marshmallows and add them to your microwave safe bowl.
Microwave your marshmallows and butter for 30 - 60 seconds.
Once they have heated, stir them up.
Microwave them again for 30 seconds and stir again.
Repeat this until your marshmallows and butter are melted and combined.
Note: you can also melt them together on the stovetop, for those instructions see above in the post.
Now, slowly add in 7 cups of cheerios, stirring as you add them.
once your cheerios are evenly coated in marshmallow, move your mixture into your pre-greased pan.
Use your spatula and lightly press your treat mixture down into the pan so that it is the same thickness across the pan.
Let your treats cool for about 30 minutes so they are easier to cut.
Take a knife and cut your treats into 16 squares.