Pre-heat the oven to 120C or 100C Fan. Clean your bowl and utensils with lemon juice or white wine vinegar and dry with kitchen paper.
Carefully separate the egg whites and add to the bowl. Mix on a medium-high speed for around 2 minutes until the egg whites are foamy, similar to bubble bath or shaving foam.
Whisk for another 2-3 minutes, until soft peaks form.
Once soft peaks have formed, gradually add the sugar, 1 tbsp at a time. Add the cornflour, vinegar and vanilla. Increase speed to highand mix until stiff peaks have formed, around 3 minutes.
On a large, lined baking tray, divide the mixture into 6 circles- around 2-2.5" in diameter. Bake in the centre of the oven for 1 hour 10 minutes, then turn the oven off and leave them in the oven for an hour to prevent them from cracking.
When the meringues are cool, whip the double cream and Biscoff until soft peaks form- be careful not to overwhip. Add the cream onto the top of each meringue.
For the Biscoff drizzle, melt 3 tbsp of Smooth Biscoff spread in the microwave for around 10-20 seconds, then drizzle over the meringues with a spoon or piping bag. Then, add a biscoff biscuit on the top of each meringue.