1.Divide up the popcorn into two large bowls for mixing in the colors.
2.Next, take a large saucepan and combine the sugar, half & half, corn syrup, and salt. Mix together.
3.Now it's time to use your candy thermometer. Insert it into the pan and cook over medium heat until all the sugar dissolves.
4.Once that is done, you're going to bring the mixture to a low boil. Make certain that you're stirring frequently until temperature reaches 230 degrees. Be patient, this does take a while, usually about 20 minutes or so. You can also check this by putting a small spoonful of the mixture into a cup of very cold water. It's ready when it forms a soft ball when added in.
5.Once the mixture reaches 230 degrees, you're going to want to stir in the vanilla. Then, go ahead and remove it from heat.
6.Next, take and divide the mixture between two heatproof bowls. Add in the red food coloring to one bowl and blue into the other bowl.
7.Stir each mixture well to get the color distributed evenly.
8.For this part, you need to work quickly. You do this by adding in colored syrup to each bowl of popcorn and then mixing it well with a large spoon or your hands. (although this will be hot so using a spoon at first will be the best approach. If you feel that it starts to get hard, just pop it in the microwave for about 10 seconds.)
9.Next, preheat the oven to 250 degrees.
10.Take and spread out each color of the popcorn onto a parchment covered cookie sheet. Put in the oven and bake for approximately 25 minutes or until crisp.
11.Once done, take out and cool on the cookie sheets.
12.Add the white chocolate into a microwave-safe bowl and melt in 30-second intervals, stirring between, until it is completely melted and not lumpy.
13.Use a fork and drizzle the white chocolate over the popcorn. Let cool and dig in and enjoy it!