Preheat the oven to 350 degrees F (175 degrees C). Spread the pumpkin seeds on a baking sheet and bake for 10 minutes, or until lightly browned.
In a medium saucepan, combine the sugar, corn syrup, butter, and salt. Cook over medium heat, stirring constantly, until the mixture comes to a boil.
Stir in the pumpkin seeds and continue to cook until the mixture reaches 300 degrees F (150 degrees C) on a candy thermometer.
Remove the pan from the heat and stir in the baking soda. The mixture will foam up. Quickly pour the mixture onto a greased baking sheet and spread it out with a greased spoon.
Allow the brittle to cool completely before breaking it into pieces.
Interesting Facts
Pumpkin-seed brittle is a traditional treat in many cultures.
It is believed to have originated in Central America and Mexico.
It is sometimes called "Mexican wedding candy".
Pumpkin-seed brittle is a great way to use up leftover pumpkin seeds.