Sort and discard any unpopped kernels from the popcorn. Spread popcorn and nuts across two 9x13-inch baking dishes (or one deep roasting dish). In a small saucepan over medium heat, melt butter, then stir in brown sugar and honey. Cook, stirring occasionally, until mixture comes to a full boil (about 6 to 8 minutes), then simmer without stirring for 5 minutes. Remove from heat and stir in vanilla. Pour hot mixture over popcorn and nuts, tossing to coat.
Bake at 250 F for 30 minutes, stirring every 10 minutes. The baking process will continue to evenly coat popcorn and nuts with caramel, and the caramel will change from gooey to crispy with a visible crackle texture. Remove from oven and spread mixture over a silicone mat or wax paper to cool. Store in airtight container for up to a week.
Per serving: 200 calories, 13 grams fat (4.5 grams saturated fat), 19 grams total carbohydrates, 14 milligrams cholesterol, 121 milligrams sodium, 2 grams fiber, 4 grams protein.
