For the pastry:
Pre-heat the oven to 180°C, line a baking tray with baking paper and spray with non-stick cooking spray.
Mix the flour, sugar, salt and olive oil together. Slowly add the water and mix well to form a pastry. Form the pastry into a flat disk wrapped in cling film and rest it in the fridge for about 30 minutes – 1 hour.
For the Tart:
Remove the pastry from the fridge and use your hands to spread the pastry into a circle with a 1cm thickness. The dough is supposed to be soft and light.
In another small mixing bowl, combine the grapes, rosemary, sugar and almond flour.
Spread the grape mixture on the pastry base, leaving a 2 cm open border around the sides. Fold the borders over to cover a little bit of the filling.
Bake the crostata in the oven for about 40 minutes, or until cooked and golden brown.
Serve with ice cream and garnish with edible flowers.