Line a sheet pan with parchment or waxed paper.
Heat the oil in a saucepan on medium to high heat.
Add 3 to 4 kernels in the oil and wait for the kernels to pop, add the rest of the 1/3 cup of popcorn kernels in an even layer, Cover the pot, remove from heat and count 30 seconds
Return the pan to the heat, Once the popping starts in earnest, gently shake the pan by moving it back and forth over the burner, As the popcorn pops, try to keep the lid slightly ajar to let the steam from the popcorn release.
Place cooked popcorn in a large bowl.
Melt butter in the empty hot pan then just drizzle the melted butter over the popcorn and toss to distribute. Add M&Ms and cake mix powder stir to coat. Spread coated popcorn onto prepared sheet pan. Drizzle with a little more than half of the melted white chocolate, tossing gently a few times with a rubber spatula to cover popcorn. Sprinkle with half of the Christmas sprinkles. Drizzle with remaining chocolate and add more sprinkles.
Allow to cool and harden for at least 30 minutes, then gently break into pieces and store in an airtight container.
