First, use a paring knife to split and scrape the vanilla bean. Put the split vanilla bean into a heavy bottom saucepan.
Now you will prepare your mixed berries. Dice the strawberries into quarters, cut the raspberries in half, and leave the blueberries whole. PRO TIP: Fresh berries will keep their shape better, but frozen berries will work as well.
Add the prepared mixed berries into the heavy bottom saucepan along with the vanilla bean.
Then, add in the sugar and the lemon juice and stir everything to combine.
Next, in a separate mixing bowl, combine the corn starch and water. Mix until it is smooth.
Add the cornstarch mix to the berries in the saucepot and mix to combine.
Cook the berries over medium to low heat and continue to stir gently. Be careful not to scald the berries with high heat. The berries will begin to soften and release juices over medium to low heat.
When the berry juice mixture begins to boil, remove the saucepan from the heat and transfer the berry compote to another bowl to cool down.
Cover the berry compote with plastic wrap. Do this by pressing the plastic wrap right up against the surface of the berries. This step will prevent a layer of skin from forming over the berries mixture.
Then, once the berries are covered in plastic wrap, place the bowl in the refrigerator until it is completely cool.
Finally, when you are ready to assemble the pavlova, you can remove the vanilla bean pod from the berry compote.