Put the sugar lumps in the pie dish with 2 tbsps. of water and cook until you have a golden brown caramel.
Remove from heat and turn dish to coat the base with caramel. Leave to set.
Wash, dry and pick grapes off bunch.
Spread them evenly over the base of the dish
Bring the milk to the boil.
Using the plastic blade, put the eggs, granulated sugar and vanilla sugar in the processor and blend for 20 seconds on speed 4, add flour, blend for a further 15 seconds then add the melted butter and pour in the milk through the feeder tube.
Blend for another 5 seconds.
You can prepare separate tarts in small individual dishes.
You can make 8 tarts by using 400g of grapes.
Bake for 30 seconds,
For a quick recipe, you need not make any caramel.
In this case, increase the quantity of castor sugar to 75 gms.
You can use cherries, prunes, sliced apples, redcurrants, blackcurrants etc. instead of grapes.