Blend raspberries and bananas with some lemon juice and put into the fridge. Cut the skin off 1 fresh pineapple and then into thin slices. Take the core out and put onto non-slip mats. Slow roast thin slices fresh pineapple in the oven until almost crispy in a low heat, 80 C. Put the roasted pineapple in the middle of the plate. Raspberry/banana mixture on top and then another pineapple with more mixture and finish off with one more layer of pineapple. Dust cocoa powder on top.