Roast the White Chocolate: Preheat your oven to 150°C (300°F) / 130°C fan / gas mark 2. Roughly chop the white chocolate and spread it in an even layer on a baking tray lined with high-quality baking parchment.
Bake for 10 minutes, remove from the oven, and give it a good stir. Return to the oven for 2 more minutes.
Let it cool completely on the tray, then chop it into rough crumbles. Store in an airtight container.
Prepare the Pineapple: Increase the oven temperature to 220°C (425°F) / 200°C fan / gas mark 7.
Slice the top and bottom off the pineapple. Stand it upright and carefully slice away the skin from top to bottom.
Remove the 'eyes' by cutting shallow 'V' shaped grooves.
Cut the pineapple in half lengthwise, then cut each half into three long wedges.
Slice off the tough inner core from each wedge.
Roast the Pineapple: Place the pineapple wedges in a high-sided baking tin and sprinkle evenly with the demerara sugar.
Bake for 15 minutes, turning the wedges once halfway through to ensure they are beautifully coated in the caramelized sugar.
Remove from the oven and set aside to cool.
Make the Crispy Rice Topping: Lay a 50cm / 20-inch strip of baking parchment on your work surface. In your largest frying pan, combine the water, granulated sugar, and sea salt.
Bring to a simmer over medium-high heat.
Let the sugar melt and begin to turn a light amber colour at the edges—do not stir it!
Once it starts colouring, add the popped rice cereal and stir constantly until every piece is coated and golden brown. Be very careful as the caramel is extremely hot.
Finish the Crispy Rice: Immediately remove the pan from the heat and fold in the butter until it's fully melted. Quickly turn the mixture out onto your prepared baking parchment, spreading it into a thin layer. Allow it to cool and harden completely.
Once set, gently smash it with a rolling pin into a mix of shards and smaller pieces.
Assemble and Serve: To serve, thinly slice the cooled pineapple wedges.
Arrange a line of the roasted white chocolate crumbles on each plate.
Top with the pineapple slices and finish with a generous sprinkle of the crispy rice shards. For an extra touch of decadence, add a scoop of vanilla or white chocolate ice cream.
When making the caramel for the crispy rice, resist the urge to stir the sugar and water mixture until it begins to colour.
Stirring can cause it to crystallize.
