After popcorn has popped, pour melted butter over the top.
Combine sugar and cinnamon together in a bowl. Pour mixture over the popcorn. Toss to coat.
Drizzle melted white chocolate over the top, toss to coat. Spread popcorn on prepared baking sheet. Allow chocolate to harden, about 10 minutes, then break into pieces. Serve.
Store leftovers in an airtight container and eat within a day or two.