Remove the grapes from the stem, give them a rinse and put them on a paper towel.

Preheat the oven to 360°F, line a 22cm springform tin with parchment paper and set aside.

Let's prepare the crumble: mix in a bowl the flour, sugar and oil. Put the mixture in the fridge.

Chop the walnuts coarsely and set aside.

Let's prepare the cake: put in a large bowl the flour and baking powder, mix well using a wisk then create a hole in the center; pour in the malt, oil and vanilla flavoring.

Start stirring with a whisk and adding water until the dough is creamy without any lump. Be careful not to add too much water or the batter will be too runny and the cake won't rise. The amount of water needed depends on the flour you use, anyway bear in mind that about half a cup should be enough.

Pour the cake batter into the tin you've prepared before, pour the grapes over it and distribute them evenly.

Crumb the cold crumble mixture over the cake, trying to cover the surface evenly. Top with the chopped walnuts.

Bake the cake for 40 minutes then do the toothpick test. If the cake is done go on baking 5 minutes with grill function only, to let the crumble become beautifully golden and crispy.

Let the cake cool on a wire rack before serving.