The day before, wash the grapes and place them in a bowl. Pour in the PASTIS DE L'ILE DE RE to cover them. Cover the bowl with cling film. Leave to macerate overnight until the grapes swell.
The next day, wash the mirabelles and cut them in half. Remove the stones.
Preheat your oven to 80°C mark 6. Place the shortcrust pastry in a tart tin and prick the base of the pastry with a fork.
Arrange the mirabelles on the pastry, skin side up. Then add the grapes to the PASTIS DE L'ILE DE RE. Sprinkle with cane sugar.
Place in the oven for 25 minutes. Leave to cool before serving.