01 - Preheat oven to 250°F and line a baking tray with parchment paper. In a clean bowl, whisk egg whites until soft peaks form. Gradually incorporate caster sugar while whisking until stiff, glossy peaks form. Fold in vanilla extract.
02 - Spoon or pipe small mounds of meringue onto the prepared tray. Bake for 1 hour, then turn off the oven and allow meringues to cool completely inside.
03 - Combine frozen berries, caster sugar, lemon juice, and orange zest in a saucepan. Simmer gently for 5 to 7 minutes until berries soften and mixture thickens. Remove from heat and cool completely.
04 - In a chilled bowl, whip double cream with icing sugar and vanilla extract until soft peaks form.
05 - Roughly crush cooled meringues. Layer meringue pieces, whipped cream, and berry compote in serving glasses or a large bowl, repeating layers as desired.
06 - Top with extra berries and fresh mint leaves if desired. Lightly dust with icing sugar before serving.