Combine the granulated sugar, light corn syrup, and water in a heavy-bottomed saucepan and stir until all sugar is moistened.

Place the pan over medium-high heat, insert a candy thermometer without touching the bottom, and bring to a boil without stirring until the mixture reaches 300°F (hard-crack stage), about 10–12 minutes.

Immediately remove the saucepan from heat and quickly stir in the baking soda, vanilla extract, and sea salt for about 10 seconds; the mixture will foam vigorously.

Pour the foaming candy onto a parchment-lined baking sheet and allow it to spread naturally into a thin layer without touching it.

Cool the honeycomb completely at room temperature for roughly 10 minutes, until hard and no longer warm.

Using a small sharp knife or cookie cutter, gently carve desired shapes (umbrella, triangle, circle, etc.) into the cooled honeycomb.

Snap the candy along the carved lines to create individual cookies, working slowly to avoid shattering.

Melt the chopped chocolate in a shallow bowl over a double boiler or in the microwave in 20-second bursts, stirring until smooth and 85°F.

Dip the shaped side of each honeycomb piece into the melted chocolate, letting excess drip off, and return to parchment paper chocolate-side up.

Sprinkle sesame seeds onto the wet chocolate and let the cookies set at room temperature for 15 minutes (or chill 5 minutes in the refrigerator) until the chocolate is firm.