Add the butter and sugar in a bowl fitted with paddle attachment to a stand mixer. Sift the flours into the bowl and mix on low speed.

Mix the apple cider vinegar and cold water in a small bowl. Spoon in one spoon at a time until the mixture is mixed lightly throughout. (it should resemble wet sand)

Transfer the mixture on a cling film and chill it for 1 hour to overnight.

Preheat the oven to 435° F/ 220° C. Dust the surface with a little bit of flour, roll out the dough to about ¼ inch thick. Bake for 20 minutes or until crispy golden brown.

Once baked, let it cool on a cooling rack.

Preheat the oven to 375 °F / 190 °c . On a roasting dish, add the grapes. Sprinkle the sugar and drizzle the rose water and water.

Roast for around 20-25 minutes or until the grapes are juicy and soft.

Remove from the oven and let it cool.

Add the mascarpone, heavy cream into a bowl. Beat for about 3-4 minutes on medium (6) speed with a whisk attachment on a stand mixer.

Sift the icing sugar into the whipped cream. Whisk all the ingredients for another 5 minutes on medium speed. Chill in the refrigerator until you are ready to use.

Once the tart base is cooled, scoop spoonfuls of mascarpone cream on the tart and spread it. Top it with the roasted grapes.

Assemble fresh before you want to serve.