Contents
This traditional Finnish flatbread recipe, known as Rieska, is a quick and wholesome way to use up sourdough discard. Made with hearty rye flour and oats, this bread is soft, slightly tangy, and ready in under 30 minutes — perfect alongside soups, stews, or simply served warm with butter.
Equipment
- 9×13” or quarter-sheet baking pan
- Parchment paper
- Dough whisk or spatula
- Mixing bowl
- Pastry cutter or forks
- Measuring cups and spoons
- Liquid measuring cup
Ingredients
- ½ cup rolled oats
- 1 cup rye flour
- ¼ cup all-purpose flour
- 2 tsp baking powder
- ½ tsp baking soda
- 1 tsp fine sea salt
- 2 tbsp granulated sugar
- 1¼ cup sourdough discard (unfed starter)
- 4 tbsp unsalted butter, softened
- 1 cup whole milk
Instructions
- Preheat oven to 500°F (260°C). Line a 9×13-inch or quarter-sheet pan with parchment paper and lightly grease it.
- In a large mixing bowl, combine oats, rye flour, all-purpose flour, baking powder, baking soda, salt, and sugar.
- Add softened butter in chunks. Use a pastry cutter (or two forks) to cut the butter into the dry mix until it resembles coarse crumbs.
- Add the sourdough discard and lightly mix it into the dough.
- Pour in the milk and stir to form a sticky dough.
- Transfer the dough into the prepared pan and spread evenly with wet hands.
- (Optional) Let rest for 30 minutes for extra rise and tangy flavor.
- Bake for 12–15 minutes, until lightly browned and springy.
- Cool for 10 minutes, then slice and serve warm.
Notes

What is Rieska? A Taste of Finnish Tradition 🇫🇮
Rieska is a traditional Finnish flatbread that dates back centuries. Originally made by rural families in Northern Finland, it was a humble, no-yeast bread baked daily using whatever flour was on hand — typically rye, barley, or even potato. This bread has remained a staple in Finnish households thanks to its simplicity, speed, and versatility. Unlike yeasted bread, rieska is unleavened or only lightly leavened, resulting in a soft yet dense texture. It’s typically baked fresh and eaten the same day — still warm, slathered in butter, or served with soups and stews. Today, we’re giving this classic a modern twist by using sourdough discard — a tangy, eco-friendly addition that reduces food waste while adding complex flavor.⭐ Why You'll Love This Recipe
- ✅ No rise time – ready in under 30 minutes
- ✅ Uses leftover sourdough discard
- ✅ Packed with fiber-rich rye and oats
- ✅ Naturally egg-free
- ✅ Ideal for dipping, buttering, or topping with cheese
🛠️ Tools & Equipment
To make this easy rye flatbread, you'll need:- 9×13” pan or quarter-sheet baking pan
- Parchment paper
- Dough whisk or sturdy spatula
- Large mixing bowl
- Pastry cutter (or two forks)
- Measuring cups & spoons
- Kitchen scale (optional but recommended)
- Liquid measuring cup
🧾 Ingredients
- ½ cup (45g) rolled oats
- 1 cup (113g) rye flour
- ¼ cup (30g) all-purpose flour
- 2 tsp baking powder
- ½ tsp baking soda
- 1 tsp fine sea salt
- 2 tbsp (25g) granulated sugar
- 1¼ cup (200g) sourdough discard (unfed)
- 4 tbsp (57g) unsalted butter, softened
- 1 cup (240g) whole milk
- Swap rye for barley flour for a more traditional variation.
- Use plant-based milk and vegan butter for a dairy-free version.
👩🍳 How to Make Finnish Rieska with Sourdough Discard
Step 1: Prep the Oven & Pan
Preheat your oven to 500°F (260°C) — yes, really! 🔥 Line a 9×13” pan or quarter-sheet pan with parchment paper and lightly grease it.Step 2: Mix the Dry Ingredients
In a large bowl, combine the oats, rye flour, all-purpose flour, baking powder, baking soda, salt, and sugar. Whisk until evenly mixed.Step 3: Add Butter & Discard
Add softened butter in small pieces. Use a pastry cutter or two forks to incorporate it until the mixture resembles coarse crumbs. Now add the sourdough discard and cut it into the dough — it’s okay if it's not fully blended yet.Step 4: Add Milk & Combine
Pour in the milk and mix thoroughly using a spatula or dough whisk. The dough will be very sticky — that’s normal!Step 5: Spread the Dough
Transfer the dough into the prepared pan and spread it evenly using wet hands or a spatula. Optional: Let the dough rest at room temperature for 30 minutes, or refrigerate it for a few hours. This allows mild fermentation for a tangier flavor and improved texture.Step 6: Bake
Bake for 12–15 minutes, until the top is golden and springy to the touch. Let cool in the pan for 10 minutes, then slice into squares and serve warm. 🧈🍲 How to Serve Rieska
Rieska is wonderfully versatile. Serve it:- Warm with butter and flaky salt
- Alongside hearty soups like salmon chowder or lentil stew
- Topped with cheese, smoked salmon, or herbed cream cheese
- Toasted with jam or honey for a cozy breakfast
🧊 Storage Tips
- Store leftovers in an airtight container at room temperature for up to 3 days.
- Freeze slices in a zip-top bag for up to 3 months. Reheat in a toaster or oven for best results.