Prepare the sauce by combining the berries and sugar in a small saucepan. Stir over a medium heat to dissolve the sugar, then boil gently for 8 mins, stirring regularly, until thick and syrupy. Stir in vanilla extract and leave to cool completely. Whizz in a food processor until smooth.
Preheat your oven to 120°C and line a tray with baking paper.
Whisk the egg whites until they form stiff peaks when the beaters are lifted. Gradually add the castor sugar (about one tablespoon at a time) while beating, and beat well between each addition. Whisk in the salt and vanilla paste.
Drop heaped tablespoons of the meringue mixture onto the prepared tray. Finally, sprinkle the ground almonds over the meringues.
Bake the meringues for 1 hour. Switch the oven off but leave the door closed, and allow the meringues to dry out for a further hour.
Serve the meringues with fresh cream and the berry sauce. Store any leftovers in an airtight container. The sauce should be stored in the fridge.