Line a baking pan or cookie sheet with parchment paper. Grease with butter or spray with non-stick cooking spray. Set aside. Keep close.
In a large pot or dutch oven, melt butter over medium heat. Allow bubbles to rise and fall to brown butter. 2 to 3 minutes.
Add 6 cups mini marshmallows and stir until just completely melted. Stirring constantly. 3 to 4 minutes. Don't overcook or the mixture will harden.
Remove or take off the heat and immediately stir in vanilla and salt. Stir. Working quickly, fold in the cereal and 1 cup of mini marshmallows. Stir/fold together until well coated and added marshmallows just start to melt but are still chunky.
Transfer quickly to prepared pan and pat down with butter stick wrapper lightly and evenly into the pan. Let cool for a few minutes.
Melt 1/2 cup mini marshmallows in a microwave safe cup for 15 to 20 seconds on high. Remove and using a spoon or a fork, quickly drizzle melted marshmallow on top of mixture. Make any pattern you like. Get creative. Set aside to cool completely to room temperature. 1 hour. Slice into squares and enjoy.
Cover and store at room temperature for up to 3 days. Good luck with that. Do not refrigerate.