Get ahead and preheat your oven to 150C/ 300F/ Gas Mark 2
Tear a large piece of greaseproof/parchment/baking paper, big enough to cover a large dinner plate
Put the paper on a flat level surface and place the plate on top. Use a pencil and trace the edge of the dinner plate so you end up with a large circle.
For this part, you will be using a hand blender, food blender or good old elbow grease. Crack the eggs and separate the yolks from the whites. I run them through my fingers for speed.
Add the whites to a bowl and whisk the until the have formed stiff peaks.
Add the caster sugar a little at a time whilst continuing to whisk. Add, whisk, add, whisk until all of the sugar is incorporated and the meringue is lovely and shiny and not grainy.
Add the cornflour, vanilla extract and the white wine vinegar and whisk to combine. The meringue should be firm yet malleable.
Place the paper onto a baking tray and carefully scoop the meringue onto the using the pencil circle as a guide for its shape.
Add to the oven and bake at 150C for 1 hour. DO NOT open the oven for a while. After an hour has passed, turn off the heat and allow the Pavlova to cool completely in the oven. (Creates a lovely crisp coat.)
Once the meringue has cooled, remove form the oven and put to one side for now.
Wash the blackberries, blueberries and strawberries and pat dry. Slice the strawberries in half and remove the hard centre. The other berries are small enough already.
Pour the double cream into bowl and add the icing sugar. Whip the cream until it is soft and fluffy, and the bowl can be turned upside down and nothing falls out.
Spread the whipped cream over the meringue gently trying not to break it.
Keep chilled in the fridge until needed.
When ready to serve, place the strawberries, blackberries and blueberries son the cream and garnish with a few leaves of fresh mint.