FOR THE RASPBERRY COULIS Place the sugar syrup and raspberry purée in a saucepan over medium heat and bring to a simmer. Remove from the heat and cool in the fridge.
FOR THE MERINGUE Preheat the oven to 180ºC (350ºF). Line a 23 x 33 cm (9 x 13 inch) Swiss roll (jelly roll) tin with baking paper. Place the egg whites in a clean mixer bowl and whisk with electric beaters until medium peaks form. Gradually add the sugar, a tablespoon at a time, whisking until very stiff and glossy. Spoon the mixture into the lined roll tin and smooth the surface. Bake for 8 minutes, or until golden brown. Reduce the oven temperature to 160ºC (315ºF) and bake for a further 15 minutes, or until the meringue is crispy. Sprinkle a sheet of baking paper with extra caster sugar. Turn the meringue out onto the baking paper, and peel off the baking paper from the base of the meringue. Leave to cool.
FOR THE RASPBERRY FILLING Place the cream and raspberries in a bowl and lightly mix together.
FOR THE ALMOND ANGLAISE Place the milk, cream and half the sugar in a saucepan and bring to boiling point.
In a metal bowl, mix the egg yolks and remaining sugar. Whisk in half the milk mixture, then add the remaining liquid
and whisk until well combined. Pour into a clean saucepan and heat gently, stirring constantly until the mixture reaches 84ºC (183ºF) and coats the back of a spoon, taking care not to overcook the custard or the egg will scramble. Set aside
to cool, then add the almond liqueur to taste.
TO SERVE Spread the raspberry filling evenly over the meringue. Top with three-quarters of the strawberries, blackberries and raspberries. Starting at the long end, roll up the meringue, using the baking paper to help you. Cut into slices and place in serving bowls. Drizzle with the raspberry coulis. Top with the remaining fresh berries and scatter the flaked almonds over. Dust with icing sugar and serve the almond anglaise alongside.