Welcome to your new sweet tooth addiction. Beware! Its easy to accidentally eat WAY more of this than you meant to.
Put 6 cups of cereal in a large bowl. I like a combo of sizes or shapes but with neutral flavors. This is 2 cups each of rice krispies, corn flakes, rice chex.
In a saucepan, melt 1 cup butter. Add 1 cup brown sugar, pinch of salt, 2 tsp vanilla extract. Stir constantly until it boils for a few minutes, then thickens and lightens in color.
Pour over cereal and mix. Spread on a baking sheet covered in parchment paper. Bake at 350 degrees for 7 minutes. Let cool, break into pieces, and store in air tight container.
Soooo good 
Chex are more my style. Looks delicious!