Cut the peaches in 0,5cm thick slices
In a bowl add 30g of the sugar, the juice from the lime, the skin of ½ half the lime in stripes, the rosmary sprigs and the peach
Mix gently and cover with plastic and put in the fridge to infuse for 1-2 hours. Mix gently a couple of times during infusiion
Mix, using a spoon, the Créme Fraiche with 10 g of sugar and the zest from ½ lime. Cover and keep in the fridge.
Put the oven to heat at 180°c (hot air)
Place your puff pastry on a baking tray covered with baking paper, create an edge by bending in at 1 cm around the dough. Stick the dough with a fork several times to avoid it to inflate during cooking
Cover the dough with a baking paper and add something a bit heavy on top (metal circles, pasta, rice...).
Cook for 7-8 minutes
Remove the peach, lime skin and rosemary from the bowl. Save the juice
Remove the baking paper from the tart and place the peach on the dough. Add the butter in small pieces over the peach. Brush the edges with the egg yolk. Put back in the oven for further 12 minutes
Bring the juice from the infusion to boil in a small saucepan. Mix the cornflower with a little bit of water and pour it gently into the juice while whisking. Add one of the rosemary brings and keep simmering until you have reduced the juice by at least ⅓. Remove the rosemary brig
Pour the thickened juice over the peach in the tart and put back in the oven to cook for another 20 minutes.