Put the blanched almonds in a colander and sprinkle with a little cold water. Shake off any excess water and place the almonds on a nonstick baking sheet. Sift the icing sugar over the top and bake in a preheated oven, 180°C (350°F), Gas Mark 4, for about 20 minutes until they have crystallized.
Remove the almonds from the oven and set aside to cool, then put them in a freezer bag and tap lightly with a rolling pin until they are crushed but not powdery.
Mix together the grated chocolate, dates and almonds. Spoon the mixture on to 4 slices of the buttered brioche and top with the remaining slices to make 4 sandwiches.
Heat a griddle over a medium heat and cook the brioche sandwiches for 3–4 minutes. Turn them over and cook the other side for another 3–4 minutes to make a panini.
Cut the panini in half diagonally and serve immediately with whipped cream and sprinkled with crushed almonds.