Rhubarb Custard Pie is a creamy Finnish pie made with a buttery crust, fresh tart rhubarb, and a smooth custard-style filling. This traditional Finnish summer dessert is especially popular in Finland, where kermaviili is used to create a light and tangy custard. The pie is simple to make and is a delicious way to use fresh garden rhubarb during the season.
A Summer Rhubarb Pie From My Childhood
This Rhubarb Custard Pie is one of those recipes that has stayed with me since childhood. My mother used to bake it every summer at our cottage once the rhubarb in the garden was ready to harvest. We had large rhubarb plants that seemed to thrive without much attention. As soon as they were ready, this pie was often the first thing she would make.
The combination of tart rhubarb, soft custard filling, and a buttery crust is something I have always loved. It is simple, rustic, and very comforting.
Now I have a few rhubarb plants growing in my own garden in Helsinki. Every summer I wait for the first harvest, knowing exactly what I want to bake. I also recently received a generous bunch of rhubarb from a family member, so it has truly been a proper rhubarb season.
A Finnish Way to Make Rhubarb Custard Pie
Even though this is known as a Rhubarb Custard Pie in English, it is very much inspired by Finnish home baking. In Finland, we often make the filling with kermaviili, a cultured dairy product that creates a light, creamy, and slightly tangy custard.
It pairs beautifully with rhubarb, balancing its natural tartness without making the pie too heavy.
Cardamom is another classic Finnish baking ingredient used in this pie. It adds a warm, aromatic flavor that works surprisingly well with rhubarb and custard.
If you cannot find kermaviili, you can easily substitute it with sour cream thinned with a little milk. It gives a very similar texture and keeps the filling smooth and light.
The Best Way to Enjoy Rhubarb Season
What I love most about this Rhubarb Custard Pie is how it celebrates the season. It does not try to hide the rhubarb but lets it shine in every bite.
The pie is best served once it has cooled and the filling has set properly. You can enjoy it on its own, or serve it with whipped cream or vanilla ice cream for an easy summer dessert.
Whether your rhubarb comes from your own garden, a local market, or a generous friend, this is one of the best ways to use it. The full recipe is below.
If you enjoy baking with rhubarb, you might also like my Rhubarb Frangipane Cake. For more Finnish summer baking, try my Finnish Apple Cake or my Wild Blueberry Pie, made with sweet Nordic blueberries when they are in season.
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Finnish Rhubarb Custard Pie
Equipment
- 11-inch (28 cm) springform pan
- Parchment paper
- Small saucepan
- Mixing bowls
- Electric mixer or hand mixer
- Whisk
- Rolling Pin
- Measuring cups and spoons
Ingredients
For the Crust
- 150 g (⅔ cup) unsalted butter softened
- 100 g (½ cup) granulated sugar
- 1 large egg
- 375 g (3 cups) all-purpose flour
- 1 tsp baking powder
- 2 tsp vanilla sugar or 1 tsp vanilla extract
For the Filling
- 300 g (about 3½ cups) fresh rhubarb sliced into small pieces
- 50 g (¼ cup) granulated sugar
- 1 tbsp water
- 200 g (¾ cup) kermaviili (Finnish cultured sour cream)
- Substitute for kermaviili: Use ¾ cup (180 ml) full-fat sour cream, thinned with 1–2 tablespoons milk if needed.
- 1 large egg
- 100 g (½ cup) granulated sugar
- 2 tsp vanilla sugar or 1 tsp vanilla extract
- 1 tsp ground cardamom
Instructions
Prepare the Rhubarb
- Place the sliced rhubarb, ¼ cup (50 g) sugar, and 1 tablespoon water in a small saucepan. Bring to a gentle boil and simmer for 2–3 minutes, just until the rhubarb begins to soften. Remove from the heat and let cool completely.
Make the Crust
- Preheat the oven to 400°F (200°C).
- Beat the softened butter and sugar until light and fluffy. Add the egg and beat until well combined.
- In a separate bowl, whisk together the flour, baking powder, and vanilla sugar. Gradually add the dry ingredients to the butter mixture until a soft dough forms.
- Cover and refrigerate the dough for about 30 minutes.
Prepare the Pan
- Line the bottom of an 11-inch (28 cm) springform pan with parchment paper.
- Roll out the chilled dough and gently press it into the bottom and about 1½ inches (4 cm) up the sides of the pan.
Make the Filling
- In a large bowl, combine the cooled rhubarb, kermaviili, egg, remaining ½ cup (100 g) sugar, vanilla sugar, and ground cardamom. Stir until smooth and well combined.
- Pour the filling into the prepared crust.
Bake
- Bake for 35–40 minutes, or until the filling is set and the crust is lightly golden around the edges.
- Allow the pie to cool before slicing and serving.
Notes
- Full-fat sour cream thinned with a little milk
- Crème fraîche mixed with a little plain yogurt
- Whole milk Greek yogurt, if that’s all that’s available
Cardamom is a classic flavor in Finnish baking and pairs beautifully with tart rhubarb.
Serve the pie slightly warm or chilled with whipped cream, vanilla sauce, or a scoop of vanilla ice cream.
