Our whole family has a sweet tooth, so this caramel-drizzled mix of popcorn, almonds and cereal goes quickly. My "off-limits" batches are divided into plastic bags, tied with ribbon and shared with all the snackers on my Christmas list.
In a very large heat-proof bowl, combine the popcorn, cereal and almonds; set aside. In a large heavy-duty saucepan, melt butter; stir in corn syrup and brown sugar. Cook and stir over medium heat until mixture comes to a boil. Reduce heat to medium-low. Cook 5 minutes longer, stirring occasionally.
Remove from the heat. Stir in baking soda. (Mixture will foam up and get lighter in color.) Carefully pour over popcorn mixture; stir to coat evenly.
Transfer to two 15x10x1-in. baking pans coated with cooking spray. Bake at 250° for 45 minutes, stirring every 15 minutes. Spread on waxed paper to cool. Store in airtight containers.