Heat coconut oil in a large pot over medium high heat. Add a few kernels to pan and cover. When most of these kernels have popped, add remaining kernels and cover pan. Shake pan as corn pops until popping slows to a few pops per second. Empty the popcorn into a large paper bag; add salt and shake to combine. Transfer to a large bowl, discarding any unpopped kernels. Set aside. 

Preheat oven to 250°F. Line a rimmed baking sheet with parchment paper; set aside.

In a 2-quart, heavy saucepan, combine butter, brown sugar and corn syrup. Stir over medium-high heat until butter is melted. Clip on the candy thermometer and cook, without stirring, until mixture reaches 235°F. (soft ball stage). Remove from heat and add the baking soda (mixture will foam up), then stir in the maple flavoring. Pour the hot caramel over the popcorn and use 2 large spoons to mix the popcorn until it is well coated with the caramel (use caution...caramel is very hot!). Transfer caramel corn to prepared baking sheet. Sprinkle with the chopped pecans and spread out popcorn to an even layer. 

Bake popcorn for 1 hour, stirring every 15 minutes to distribute the caramel. Cool completely and store in an airtight container. 

Makes about 7 cups. Recipe can be doubled. If doubled, we recommend using a very large bowl for mixing the hot caramel into the popcorn then pouring the caramel corn onto two separate sheets for baking.