Lightly spray a large baking sheet with vegetable cooking spray. Set aside.
In a medium-large, heavy bottomed saucepan combine the sugar, honey and water. Bring the mixture to a boil over high heat, stirring constantly.
Reduce the heat to medium-high and continue cooking and stirring until the mixture darkens and reaches 300°F.
Remove from the heat and immediately add the baking soda. Quickly whisk the mixture, just until blended. The honeycomb will grow in volume by almost 3 times its' original size, so be careful.
Immediately pour the hot candy onto the prepared baking sheet. Do not spread or touch the candy. Let the honeycomb cool completely before breaking into pieces.
Store the honeycomb brittle in an airtight container at room temperature for up to a week.
Notes
Recipe by Martha Stewart
Nutrition information is calculated using an ingredient database and should be considered an estimate. When multiple ingredient alternatives are given, the first listed is calculated for nutrition. Garnishes and optional ingredients are not included.