Chicago-Style Caramel-Cheddar Popcorn

Place racks in upper and lower thirds of oven; preheat to 275°. Place one 3.3-oz. bag unsalted or lightly salted microwave popcorn, popped (about 10 cups), in a large heatproof bowl, removing any unpopped kernels; set aside.

Heat ¼ cup honey in a medium saucepan fitted with a candy thermometer over medium until bubbling and slightly and darkened in color, about 5 minutes. Add 1 cup (packed; 200 g) dark brown sugar and 5 Tbsp. unsalted butter and bring to a boil, stirring constantly with a heatproof rubber spatula, until brown sugar and butter are melted, about 3 minutes. Continue to boil without stirring until thermometer registers 260°, 5–7 minutes. Remove pot from heat and add 1 tsp. baking soda and 1 tsp. Diamond Crystal or ½ tsp. Morton Kosher salt, stirring vigorously (be careful as the mixture will bubble up).

Working quickly, pour hot caramel over reserved popcorn and mix until evenly coated. Quickly scrape popcorn out onto a parchment-lined baking sheet and spread out into an even layer. Bake, rotating baking sheet and stirring halfway through, until crisp, 22–27 minutes. (To check if it’s done, carefully remove a piece and let it cool 30 seconds. It should be crisp.) Let cool.

While the caramel popcorn is cooling, place one 3.3-oz. bag unsalted or lightly salted microwave popcorn, popped (about 10 cups), in a large heatproof bowl, removing any unpopped kernels. Mix 4 Tbsp. unsalted butter, melted, slightly cooled, and 1 tsp. English mustard powder (such as Colman’s) in a small bowl. Pour over popcorn and toss to coat evenly. Sprinkle ½ cup cheddar cheese powder and 1½ tsp. Diamond Crystal or ¾ tsp. Morton Kosher salt over popcorn and toss again to coat.

Spread out popcorn onto another parchment-lined baking sheet in an even layer. (There will be excess cheese powder on the baking sheet.) Bake, rotating baking sheet and stirring halfway through, until crisp,12–14 minutes. Remove from oven and immediately sprinkle remaining ¼ cup cheddar cheese powder over. Toss to evenly coat.

Break caramel popcorn into bite-size clusters. Place in a large bowl; add cheddar popcorn, along with any cheese powder left on baking sheet, and toss to combine. Do Ahead: Caramel-Cheddar Popcorn can be made 5 days ahead. Store airtight at room temperature. Cook’s Note: If you’d like to make your popcorn on the stovetop, place 3 Tbsp. vegetable oil and 3 popcorn kernels in a large heavy pot, cover, and heat over medium until kernels pop. Reduce heat and add ⅔ cup popcorn kernels. Cover pot and increase heat back to medium. Shake pot to evenly distribute kernels, partially cover pot so crack is facing away from you, and cook until popping stops. Divide popcorn between two large bowls, removing any unpopped kernels.