Line a rimmed baking sheet, such as a 10x15 jelly roll pan, with parchment paper. Have it handy!
In a large 5-qt Dutch oven or spaghetti pot, combine the granulated sugar, honey, and pinch of salt. Heat mixture over medium heat, stirring until blended and sugar has dissolved some to ensure even caramelization. Cook to 295 degrees F, about 5-7 minutes depending on your stove. The mixture will turn a pretty amber color.
Remove from the heat and immediately add in the vanilla extract and baking soda, whisking the mixture vigorously. Mixture will bubble and foam up, so be careful! Working very quickly, pour the honeycomb mixture evenly onto the prepared pan. Do NOT smooth it out; it will be uneven but you don't want to break up that texture by messing with it.
Let the mixture cool completely, about 5-10 minutes, before snapping into pieces. Dip each chunk part way into dark chocolate, and sprinkle with flaky sea salt. Store any leftovers air-tight at room temperature.