Here’s an easy recipe for a Swiss rhubarb tart known as a Rhabarberwähe in Swiss-German. To my recipe, I’ve added a layer of crushed speculoos cookie for two reasons. First, to help absorb moisture from the rhubarb and creamy custard filling. And second, to add a sweet, spiced flavor that complements that tart baked rhubarb.
1 2/3 cup (200 g) all-purpose flour
1 tablespoon sugar
1/4 teaspoon salt
6 tablespoons (85 g) unsalted butter, cold
1 egg, slightly beaten
1-2 tablespoons cold water
scant 1/2 cup (50 g) speculoos cookies (e.g. Biscoff), crushed
500 g (about 4 1/2 to 5 cups) fresh rhubarb, cut into 1/2 inch pieces tossed
1/4 cup (50 g) + 1 tablespoon sugar
3/4 cup (180 ml) heavy cream (35% milk fat)
1 tablespoon sugar
1/2 teaspoon vanilla extract or paste
1. Make the dough. Whisk the flour together with the sugar and salt in a large bowl. Add the cold butter, in pieces. Using a food processor, pastry blender or two knives, cut the butter into the flour mixture, until it becomes the size of small pebbles. Make a well in the center of the mixture and add the slightly beaten egg. Add 1 tablespoon of water and stir everything together, adding up to another tablespoon of water as necessary, just until a dough forms. Shape the dough into a disk and refrigerate the dough for 30-60 minutes, until it becomes firm.
2. Line a tart pan with a diameter of about 30 cm (11.5 inches) with parchment paper. Take the dough out of the fridge and roll it out on lightly floured surface. Place it into the prepared tart pan. Using a fork, prick the bottom of the dough. Place the pan with the dough back in the fridge to cool.
3. Add the prepared rhubarb to a large bowl and add the sugar. Toss the rhubarb together with the sugar in the bowl until it’s well combined. Take the pan with the dough out of the fridge and add the rhubarb and sugar mixture, spreading it evenly in the pan over the crushed speculoos cookies.
3. Make the filling. In a large bowl, whisk the eggs, heavy cream, sugar and vanilla extract together until the well-blended. Pour the filling evenly over the rhubarb.
4. Bake the Swiss rhubarb tart on the bottom rack of your oven for about 35-45 minutes at 180°C / 350°F until the cream filling is set and the pastry has turned golden brown. Let the tart cool completely before serving.