1: Put the blueberries into a small saucepan with the lemon zest, vanilla seeds, water and sweetener. Bring to a simmer over a medium-high heat and let simmer for 5 minutes.

2: Meanwhile, in a small bowl, whisk the lemon yoghurt until smooth. Crumble the biscuits roughly into a separate bowl.

3: Once the blueberries have cooked down, stir in the cornflour paste and cook, stirring, until thickened. Remove from the heat and leave to cool.

4: When the blueberries have cooled completely, add them to the lemon yoghurt and mix lightly until swirled through.

5: Put a generous spoonful of the blueberry yoghurt into each of 4 serving glasses (150ml capacity) and layer the crumbled biscuits on top. Spoon on the remaining yoghurt mixture, top with the crushed meringue and serve immediately.