Preheat the oven to 180°C. Grease a 23 cm tart pan with removable bottom.

In a bowl, combine 200 grams of all-purpose flour, 100 grams of cold, cubed unsalted butter, and 50 grams of powdered sugar. Mix until the mixture resembles breadcrumbs.

Add 1 beaten egg and mix until the dough comes together. Press the dough into the prepared tart pan, ensuring even coverage. Refrigerate for 15 minutes.

Remove the tart shell from the refrigerator and prick the base with a fork. Line the shell with parchment paper and fill with baking beans or pie weights. Bake for 15 minutes, then remove the weights and parchment paper and bake for another 10 minutes until golden. Allow the tart shell to cool.

In a bowl, whisk together 100 grams of softened unsalted butter, 100 grams of powdered sugar, 100 grams of ground almonds, 2 eggs, and 1 teaspoon of vanilla extract until smooth.

Spread the almond mixture evenly over the cooled tart shell.

Arrange 250 grams of seedless grapes (halved) on top of the almond mixture, pressing them slightly into the filling.

Bake the tart for 35-40 minutes, or until the filling is set and golden brown. Allow the tart to cool before removing it from the pan.

Dust the tart with powdered sugar and serve.