In a large pot, combine the water, sugar, vanilla and rosemary and stir gently to combine. If using a vanilla pod, split the pod in half and scrape out the seeds.
Heat over a medium-low heat to dissolve the sugar, stirring occasionally.
Cut the fruit in half and remove the stone/pip. If the fruit is large, cut into quarters, or leave it halves if you prefer.
Once the sugar has dissolved, add the fruit to the sugar syrup and stir gently. Bring to a gentle simmer.
Let the fruit simmer for 4 or 5 minutes. Keep an eye on it and if the fruit starts to break down, remove from the heat.
Turn off the stove and let the mixture cool for an hour before removing the rosemary and transferring the fruit to a clean, sterile glass jar. Seal and allow to cool before storing in the fridge.
Once opened, consume within a few days.
I like this recipe slightly less sweet but if you prefer, you can increase the sugar to 2 cups for every 2 cups of water.
Be sure to use pure vanilla bean paste or a vanilla pod. Every day vanilla essence won't give as nice a flavour.
For another great use for stone fruit when its plentiful, try my Summer Fruit Tart.