Prepare Your Pan: Line an 8×8-inch square baking dish with nonstick foil or parchment paper.
Heat the Sugar Mixture: In a heavy-bottomed saucepan, combine sugar, corn syrup, and vinegar. Set over medium heat, stirring gently until the sugar completely dissolves.
Bring to 300°F (Hard-Crack Stage): Stop stirring and let the mixture come to a boil. Use a candy thermometer to monitor the temperature closely. When it reaches 300°F, remove from heat.
Add Baking Soda: Quickly whisk in the baking soda. The mixture will foam up and expand rapidly.
Pour and Let It Set: Immediately pour the foamy mixture into the prepared pan. Allow it to cool at room temperature for about 2 hours.
Break Into Pieces: Once hardened, lift the honeycomb from the pan and break it into 1-inch chunks.
Optional: Chocolate Coating: Melt chocolate wafers and dip each honeycomb piece into the melted chocolate. Let the chocolate set completely before serving.
