Measure cashews and soda in separate bowls. Have butter, cashews, and soda ready within reach
Butter two baking sheets and set aside
Combine corn syrup, sugar, and water into a pot. Add thermometer to pot and bring mixture to a boil
Stirring constantly, continue to boil mixture until reaches soft ball stage (230 degrees)
Add butter, combine thoroughly and continue to boil until thermometer reaches hard ball stage (280 degrees)
Add cashews, combine thoroughly and continue to boil until thermometer reaches hard crack stage (300 degrees)
Turn off heat and add baking soda. Stir rapidly and combine thoroughly
Immediately pour mixture out onto buttered baking sheets and spread around as thinly as possible
Allow to cool completely then break into rustic pieces
Store in airtight container away from heat and moisture