I found this recipe here.
I used the whole 20.5 ounce box of Lucky Charms, but found that it was an excessive amount. I could not fit it all in my bundt pan and it was hard to mix in any of my bowls. I did not put in any peanuts. I only could get about a 1/2 cup of the rainbow marshmallows from the box.
1 large box (20.5 ounces) of Lucky Charms cereal
1 cup of mini pretzels
2 cups of mint chocolate M&M?s candies
1 cup of shelled dry roasted peanuts (optional)
1 (16 ounce) bag of mini marshmallows
1 stick (1/2 cup) of butter
1/3 cup of Rainbow sprinkles
First coat a 10-inch Bundt pan with cooking spray.
Add 2 tablespoons of rainbow sprinkles in the bottom of the pan, then add a circle of green M&M?s.
Next separate 2 cups of the rainbow marshmallows from the box of Lucky Charms. (This is where I could only get a 1/2 cup of those marshmallows)
Then in a large heatproof bowl, stir the remaining cereal, pretzels, peanuts, M&M?s, and sprinkles. Do not put in the 2 cups of rainbow marshmallows.
Next melt the butter in a large pan over low heat, stir occasionally. Then add the mini marshmallows and stir until smooth.
Then pour the marshmallow mixture over cereal mixture; stir with a large rubber spatula. Then stir in the rainbow marshmallows from the cereal in at the end so that when you transfer them to the Bundt pan they will be on the bottom of the pan.
Press the marshmallow-coated popcorn mixture firmly into prepared pan. Cover and let set at room temperature for at least 2 hours or until cool and firm to the touch.
Run a butter knife around the sides of the pan to loosen cake. Invert pan onto a serving platter to remove cake.