Put 12 cups popped popcorn into the largest mixing bowl you have; if the popcorn is still hot from popping, let it cool 2–3 minutes so it is only warm, not hot.
Melt 1 package (1 lb) almond bark in a double boiler or in a microwave-safe bowl following the package directions, stirring frequently so it melts evenly and does not harden.
Remove the melted almond bark from heat and let it cool for 1–2 minutes so it is still pourable but not so hot that it will melt the candies.
Pour the melted almond bark evenly over the popcorn and gently stir with a large spatula or spoon until the popcorn is coated.
Spread the coated popcorn in an even layer on waxed paper or parchment paper.
Immediately sprinkle 1 1/2 cups M&M’s and 1 1/2 cups dry roasted salted peanuts evenly over the coated popcorn; if the candies begin to melt, wait a little longer for the coating to cool before sprinkling.
Let the mixture sit at room temperature until the almond bark is completely set and dry, then break into clumps and serve or store.