Banana tart tartin with chocolate sorbet

Chocolate sorbet

• 60 g raw sugar
• 30 - 50 g cocoa powder (70% cocoa), to taste
• 580 g cold water
• 30 g glucose syrup

Iced puff pastry

• 40 g ice cubes
• 90 g unsalted butter, frozen and cut into cubes (2 cm)
• 100 g plain flour, plus extra for dusting
• ¼ tsp sea salt

Filling

• 60 g unsalted butter, plus extra for greasing
• 150 g white sugar
• 30 g crystallised ginger
• 20 g water
• ¼ tsp ground cinnamon
• 1 pinch ground nutmeg
• 1 tsp natural vanilla extract
• 4 ripe bananas, cut into halves lengthways