Remove stones and cut the plums into desired size – halves or quarters depending on size. Add the cinnamon, vanilla paste, sugar or maple syrup and cornstarch and toss through gently.
Using a pastry cutter, cut the butter into the flour and sugar until it is incorporated but still quite chunky. The chunks do need to be small, but it is quite okay if some of them are a little smaller than a kidney bean.
If using a food processor, pulse one or two times, or until ready, and turn out into a bowl. Don’t be tempted to add the water to the food processor, as it is too easy to overwork the pastry.
Using a bread and butter knife, begin to mix the cold water into the flour and butter. This is the step most people need to keep practising; you will never use the same amount of water twice as it depends on the freshness of the flour, the humidity, the temperature and if any of your butter has melted. Also, the higher the percentage of wholemeal flour, the more water needed. The idea is to add a small amount of water, begin to cut and mix it in with the knife.
As you continue to add the water, little bit by little bit, you are cutting the wet bits into the dry bits, cutting, mixing and stirring. You use only as much water as you need. By cutting the wet dough into the dry bits, you avoid using too much water (another reason for tough pastry). Once all the mix looks moist, bring it together into a ball, DO NOT KNEAD OR PLAY WITH IT. Flatten the ball, wrap and chill long enough to take the softness from the butter, approx. 20 minutes.
Roll out pastry to approx 30–35cm diameter circle. Fold and move the pastry to the baking tray and unfold. Depending on the size of the tray, it may overhang the sides a little – that is fine. If the weather is very hot you may need to give it a couple of minutes in the fridge.
The pastry should be chilled but not so firm that you can’t fold the sides inward.
Either arrange the prepared fruit in an attractive pattern, or simply pile it into the middle and gently spread to leave a border of approx 8cm. Fold pastry border over fruit, peeling it from the paper underneath as you go. Sprinkle with a little extra golden caster sugar if desired. If required, trim the sides of the baking paper to fit the tray.
Place into a hot oven (200°C) for approx. 15–20 minutes, then reduce to a moderate oven (180°C) for approx. 35 minutes, or until the pastry is lightly golden and juices are bubbling. Don’t be worried if the juices look too watery, they will thicken as they cool a little.
Honey and Cinnamon Labne
Place a sieve lined with four layers of muslin (cheesecloth) over a bowl. Pour or spoon in the yoghurt and allow it to drain in the fridge for 2 – 3 hours. The longer it sits, the firmer it will become.
Sweeten to taste with honey. Flavour with vanilla and cinnamon as desired.
Place a slice of the rustic tart on a plate with a generour dollop of honey and cinnamon labne.