470 ml fresh cream
2 tsp vanilla bean paste
270 g caster (superfine) sugar
65 g brown sugar
95 g liquid glucose
65 ml water
325 g unsalted butter
40 g golden syrup
pinch of salt
4 g bicarbonate of soda
65 g good-quality milk chocolate, broken into pieces
190 g good-quality dark chocolate, broken into pieces
vegetable oil spray, for greasing