Pop your popcorn using your preferred method. For stovetop: heat 1–2 tablespoons neutral oil in a large pot over medium heat. Add 1–2 test kernels; when they pop, add the remaining kernels, cover, and shake occasionally until popping slows to several seconds between pops. For microwave: use a plain, unsalted microwave popcorn bag or a microwave popcorn bowl with loose kernels.

Transfer the popped popcorn to a large bowl and remove any unpopped kernels so they don’t end up in the finished snack.

Add the Oreo cookies to a plastic zip-top bag and seal. Crush with a rolling pin until you have a mix of pea-sized pieces and smaller crumbs. Alternatively, pulse a few times in a food processor, stopping before the cookies turn to fine powder.

Place the white chocolate chips or candy melts in a microwave-safe bowl. Add the coconut oil or shortening if using. Microwave in 20–30 second bursts, stirring after each interval, until melted and smooth (about 60–90 seconds total). If the mixture looks slightly thick or grainy, keep stirring; it often smooths out as it cools slightly.

Pour the melted white chocolate over the bowl of popcorn. Sprinkle in the fine sea salt. Use a large spatula or clean hands to gently toss and fold until most of the popcorn is evenly coated. If your bowl is very full, work in two batches to avoid crushing the popcorn.

While the white chocolate is still warm and tacky, sprinkle the crushed Oreos over the coated popcorn. Toss gently to distribute the cookie pieces throughout. If using mini chocolate chips or sprinkles, add them now and lightly fold them through.

Line a large baking sheet or tray with parchment paper. Spread the Oreo popcorn mixture into an even layer, avoiding deep piles. Let sit at room temperature for 15–25 minutes, or until the chocolate is set and the popcorn feels dry to the touch. If the room is warm, chill the tray in the refrigerator for about 10 minutes, but do not leave it in too long or the popcorn may soften from moisture.

Once set, break the Oreo popcorn into clusters. Drizzle with melted dark or milk chocolate if desired and let set briefly. Transfer to a serving bowl or portion into treat bags and enjoy.

Store any leftover Oreo popcorn in an airtight container or zip-top bag at room temperature, away from heat and humidity. For best texture, enjoy within 2–3 days; it can remain tasty up to about 4 days if well sealed.