In a medium sauce pan on medium heat, combine the butter, sugar, heavy cream, and salt. Bring to a boil stirring constantly. Boil for approximately five minutes, stirring occasionally, making sure not to burn the sugar. Then stir in the baking soda.
Pour the caramelized sugar over the popcorn and toss to distribute evenly. Place popcorn on the buttered baking sheets and sprinkle the pecans on top. Place in the oven and bake for thirty minutes. Stir the popcorn every ten minutes while baking.
Remove from the oven, let the popcorn cool and break into pieces. If you would like a little spice, sprinkle to taste with cayenne pepper. Enjoy!!