Rhubarb and custard crumble slice

A wonderfully crisp rhubarb and custard crumble slice – an absolute must-bake during rhubarb season and for the May bank holiday! Perfectly balanced in flavour, featuring an aromatic shortcrust pastry made with brown sugar, cinnamon and ginger, a rich homemade vanilla crème pâtissière, and plenty of vibrant pink rhubarb. It’s simply impossible not to love this combination. Highly recommended!

Ingredients for the shortcrust pastry:

• 2½ cups plain flour
• ½ cup finely ground walnuts or pecans
• ½ teaspoon baking powder
• 220 g cold butter
• 1 cup light brown sugar
• a pinch of salt
• 1 large egg
• 1 teaspoon ground cinnamon
• 1 teaspoon ground ginger

Place all the pastry ingredients into a food processor and pulse until the mixture resembles coarse crumbs. Alternatively, make the pastry by hand: chop the butter into the dry ingredients using a knife, then briefly bring the mixture together. Transfer the crumble mixture to a bowl, cover and chill in the refrigerator for 30–60 minutes.

Remove the pastry from the refrigerator. Scatter half of the crumble mixture into a 23 x 34 cm baking tin lined with baking parchment. Press firmly into the base to create an even layer. Chill again for 30 minutes.

Bake at 180°C for 15–20 minutes, or until lightly golden.

Ingredients for the vanilla crème pâtissière:

• 600 ml milk
• 6 egg yolks, from large eggs
• 100 g sugar (preferably at least half vanilla sugar)
• 40 g plain flour
• 40 g potato starch

Place 150 ml of the milk, the egg yolks, sugar, flour and potato starch into a bowl. Blend until completely smooth and free from lumps.

In a large saucepan, bring the remaining 450 ml milk to the boil. Once boiling, pour in the blended mixture and reduce the heat to medium. Cook, whisking constantly and vigorously, until the custard thickens and comes to the boil. Continue cooking for approximately 30 seconds, stirring continuously. Remove from the heat. Cover the surface directly with cling film to prevent a skin from forming and leave to cool completely. Do not stir again.

Ingredients for the rhubarb filling:

• 600 g rhubarb, cut into 1 cm pieces (no need to peel the stalks)
• 3 tablespoons potato starch
• 3 tablespoons sugar
• 1 teaspoon ground cinnamon
• 1 teaspoon ground ginger

Place all the filling ingredients into a bowl and mix thoroughly. Set aside until needed.

Assembly:

Spread the rhubarb filling evenly over the partially baked pastry base. The base can still be warm from the oven. Carefully spread the cooled vanilla custard over the rhubarb layer. Remove the remaining crumble mixture from the refrigerator and sprinkle evenly over the top. If the pastry has formed a solid dough, simply grate it over the filling using a coarse grater.

Bake at 180°C for approximately 40 minutes. Remove from the oven and allow to cool before slicing.

Enjoy!