For the pumpkin seed brittle: Spray a cookie sheet or jelly roll pan and set aside.
Cook the sugar, corn syrup and 1/2 cup water together in a heavy skillet until the mixture reaches between 223 and 234 degrees F (the thread stage) on a candy thermometer. Immediately add the butter and pumpkin seeds, stirring constantly. When the candy turns a caramel color, remove it from the heat and quickly add the baking soda, vanilla and pumpkin pie spice. Stir to combine. Pour onto the prepared cookie sheet and spread as thinly as possibly with the back of an offset spatula, using extreme caution not to get burned. Let cool completely, then break into small pieces.
Crush half of the brittle into small pieces to be used in the truffle covering; save the remainder for eating.
For the truffles: Melt the chocolate over a hot water bath in a double boiler, then add the butter; mix well to fully incorporate. Fold in the pumpkin puree and pumpkin flavoring. Pour into a clean container and put into the refrigerator to set up, or pour into prepared chocolate molds. If you are hand rolling truffles, let the truffle mix come to room temperature before forming into balls.
Use a melon baller to scoop the mixture into balls, then roll them in the crushed pumpkin seed brittle to finish them off.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.