Measure out your cereals and mix them together in a large bowl. Set aside.
Measure out your additional cup of mini marshmallows, set aside.
Line a 8-9 inch pan with parchment. Lightly spray with cooking spray if not non-stick.
In a large pot, melt your butter. Continue cooking butter until is browned, stirring until the milk solids have browned and the butter smells nutty. Browning the butter is optional, but recommended. If you have never browned butter I recommend doing this in a stainless or light color bottomed pan so you can see the change in the butter from yellow to golden brown. As soon as butter has reached optimal browned level, add 12 oz of marshmallows, and vanilla extract. Stir over medium low for about 1 minute, until marshmallows have melted.
Remove from heat, and stir in cereal.
Once cereal has been mostly mixed into marshmallow, pour in additional cup of marshmallows. This will create bites with marshmallow pockets or chunks.
Pour mixture into prepared pan, use butter wrapper to press into the pan.
Let treats cool for at least 30 minutes before cutting, allowing them to set.
Cut into 16 squares, store in an airtight container. Enjoy!
