Shorten the leaf base of the two pineapple fruits. Halve the fruit lengthways and hollow out a large area, but not too deeply. Wash the blueberries and pat dry with paper towels.
Beat the egg white until stiff, gradually adding the powdered sugar. Lift the blueberries under the egg whites.
Pour the egg white and blueberry mixture into the pineapple half up to a little over the edge.
Wash the raspberries and pat dry. Lightly press 5 raspberries into the egg whites.
Grill directly for 7 minutes with the lid closed and on a mild heat.