1/4 tsp Gelatin unflavored
1 tbsp cold water
1 1/2 cups white sugar
1/2 cup light corn syrup
1/2 cup water
1 tbsp baking soda sifted
1 1/2 cups dark chocolate, melted and tempered for dipping
Line a 9×9 pan with parchment paper, with extra paper hanging over the sides. Alternatively, butter and dust the pan with flour. Tapping out the excess flour.
In a small bowl, sprinkle gelatin over 1 tablespoon cold water and allow to bloom.
In a heavy bottomed medium saucepan with high sides, mix sugar, corn syrup and 1/2 cup water together. Heat over medium heat and stir until sugar dissolves and mixture comes to a boil. Clip on candy thermometer onto the side of the saucepan and cook without stirring until the syrup reaches 310 F.
Remove from heat and let sit for two minutes undisturbed, the bubbling will subside, and the temperature will drop. Add gelatin and whisk, be careful, the sugar syrup will bubble up. Sprinkle baking soda over syrup and whisk vigorously. Return mixture to the heat and whisk for 30 seconds. The sugar will expand in the pot, a lot!
Quickly pour into prepared pan, it should come out in a big blob. Do not spread the mixture, just let it settle into the pan. Leave the pan undisturbed, and allow the candy to cool completely (about 2 hours or overnight) before removing from the pan.
Either break into odd pieces or cut into squares. This is an incredibly messy process, but fun! To cut into squares – using a serrated knife, score the candy at 1-inch intervals. Snap the candy apart at the score lines. Then score and break into squares.
Melt chocolate melts in a double boiler (or bowl sitting above a pot of boiling water). Dip sponge candies in chocolate, tap off excess. Chill in the fridge to set the chocolate shell.