I have tried a bunch of different caramel popcorn recipes.  I am a sucker for soft caramel corn not the crunchy stuff for me.  This is by far the best one that I like.  It is super easy and goes really far.  Just make sure that you have others you are making it for or you might end up eating the whole thing.  I know that is what happens to me:)

Ingredients:

• 1 cup butter (2 sticks)
• 2 cups sugar
• 1 cup powdered vanilla whey protein (found in any health food aisle from Wal-mart to your everyday grocery store)
• 1/2 cup light corn syrup
• 1/3 cup water
• 1 teaspoon vanilla
• 1/2 teaspoon salt
• 3/4 teaspoon baking soda
• 2 large bowls of popped corn

Directions:

In a medium saucepan, combine the butter, sugar, whey protein, corn syrup and water. Cook over medium heat until the mixture barely comes to a slow boil. It should still look very light in color. Take the pan off the heat and stir in the vanilla, salt and baking soda. Pour the caramel mixture over two large bowls of popped corn (about 1 cup unpopped kernels that have been air popped) and mix to combine.

Recipe Source: MelsKitchenCafe