"The great thing about sponge toffee is it's a bit of a science project," he says. People are fascinated watching it being made.
Sugar, corn syrup and water are combined and heated; the mixture expands significantly when baking soda is added. "You just bring it up to 300 F (150 C) and add a bit of vanilla and some baking soda, explosion, pour it out, let it cool, cover it with chocolate and then put whatever you want with it," Brans explains.
The finished product can be topped with anything from chopped nuts to ginger and dried cherries or enjoyed plain. Provide treat bags or small take-out boxes so people can tote a few pieces home.
625 ml (2 1/2 cups) granulated sugar
150 ml (2/3 cup) corn syrup
75 ml (1/3 cup) water
20 ml (4 tsp) baking soda
10 ml (2 tsp) vanilla
To a medium saucepan, add sugar, syrup and water. Stir over medium-high heat until sugar dissolves and continue to cook until a thermometer reaches 150 C (300 F), the hard-crack stage.
Remove from heat, add vanilla and stir in baking soda. Mixture will grow. Then pour onto a parchment-lined baking tray. Let cool. Break into pieces.
1 l (4 cups) chopped dark chocolate
Tray of sponge toffee
500 ml (2 cups) chocolate pastilles or chips (for tempering)
In the top of a double boiler, melt chopped chocolate until temperature reaches 50 C (122 F). Remove from heat and add chocolate pastilles. Stir until melted, bringing temperature down to 27 C (81 F). Return to heat and bring temperature of chocolate up to 30 C (86 F). (If using milk chocolate, melted temperature is 45 C/113 F, cooled temperature 27 C/81 F and reheated temperature is 29 C/84 F.)
Pour half onto cooled sponge toffee and spread evenly with a palate knife. When hardened, flip over and repeat. Let set and cut into pieces.
Source: Chef Paul Brans, creative lead, O&B Artisan.