In medium saucepan over medium-low heat, stir marshmallows and butter until marshmallows are melted and mixture is smooth. Remove from heat. Stir in vanilla extract.
Pour mixture over popcorn in bowl. Toss well to coat popcorn evenly.
Line baking sheet with foil. Spray hands with nonstick cooking spray then scoop about 1 cup popcorn mixture. Shape mixture into cone, keeping base flat. This forms one tree. Sprinkle tree with green and blue decorating sugars; place tree on baking sheet. Repeat to make additional trees.
Pipe frosting on trees to make garland then decorate with colorful candies and miniature silver dragees.
Notes
Serving suggestion: Place each tree on sugar cookie, if desired, and decorate serving tray with shredded coconut to resemble snow.Tips: Start the recipe with unflavored white popcorn for best color and flavor. Make colored sugar by adding food coloring to sugar then stirring in bowl or shaking vigorously in sealed container. Add more food coloring for more intense tones.