Line a large, rimmed baking sheet with aluminum foil and coat it with cooking spray. Spray a spatula with cooking spray as well. Set both aside.
Spread the jelly beans in an even layer over the prepared baking sheet.
In a large soup pot or Dutch oven, mix the sugar, corn syrup, and water. Bring the mixture to a boil over medium heat. Do not stir. Boil for 10 to 12 minutes, or until the syrup turns golden and reaches the hard crack stage.*
Remove the pot from the heat. Carefully stir in the butter, baking soda, and salt. The mixture will foam up. Keep stirring for 4 to 5 minutes, or until it turns shiny.
Quickly pour the hot mixture over the jelly beans and spread it with the greased spatula.
Let the brittle cool completely. Once it has hardened, invert it onto a clean work surface.
Turn the brittle out onto a clean dish towel and peel off the foil, then break the brittle into bite-sized pieces.
Serve right away or store in an airtight container.
Notes
Hard crack stage: To test without a thermometer, drop a bit of the syrup into cold water. If it forms hard, brittle strands, it’s ready.
Work quickly: Once the mixture is poured, spread it fast - brittle hardens in seconds.
Use cooking spray: Spray your spatula and foil well to prevent sticking.
Storage: Keep in an airtight container at room temperature for up to two weeks. Avoid humidity.
Gifting idea: Wrap pieces in cellophane bags or tuck them into Easter baskets for a festive treat!