Preheat the oven to 350 F. Have ready an oven proof bowl or large pot that will accommodate all of the popped popcorn and still have room to stir.

Pop the popcorn in the olive oil however you are most comfortable doing so (if you have a hot air popper, you can definitely skip the oil--my fallback is to pop in extra virgin olive oil on slightly under medium heat, shaking the pan regularly). Dump the popped popcorn into your oven proof bowl and place in the warm oven.

Using a heavy bottomed 4 qt saucepan, gently stir the water, sugar, butter and corn syrup over medium high heat until the butter is melted and the sugar is dissolved. Place a lid on the pot for 3 minutes.

Remove the lid and insert a candy thermometer into the syrup in the pot (attach it to the side). Stirring nearly constantly (don't panic if you have to walk away for a moment), monitor the thermometer.

When the temperature approaches 300 F, take the popcorn out of the oven. When the temperature reaches 300 F, turn the heat off and stir in the salt and baking soda. Then dump the caramel into the popcorn. Stir either until it is evenly coating the popcorn or until you cannot stir anymore from stiffening. If the latter, place the popcorn back into the oven for 10 minutes, and then take out and stir again. I did not need to do this.

Dump the caramel corn onto a cookie sheet and break apart the clumps as best you are able. I did not care about mine clumping a bit, but if you do you might want to use 2 cookie sheets.

Let it cool for a few moments, and then sprinkle your candy of choice over the caramel corn. Let cool and harden completely before storing at room temperature.