To begin, preheat your oven to 225°C (fan 200°C). In a large mixing bowl, combine rye flour, plain flour, and salt. Gradually add lukewarm water while mixing with your hand or a wooden spoon until a firm, pliable dough forms. Add oil last and knead for 5–7 minutes until smooth but slightly tacky. Cover and let it rest while preparing the filling.

Continue by preparing the filling. Slice the pork belly thinly for even cooking. If using larger fish, cut into bite sized pieces but keep the skin on, it helps retain moisture and adds flavour. Mix the pork, fish, onion, salt, and white pepper in a bowl. Stir gently to avoid breaking the fish. Optional dill can be added at this stage.

Lightly flour your work surface and roll out the dough into an oval about 1cm thick. It should be large enough to encase the entire filling with some room to seal the edges tightly.

Place half the filling mixture in the centre of the dough, shaping it into a low mound. Layer the remaining filling on top, gently pressing to form a compact loaf shape. Keep at least a 4–5cm border of dough on all sides.

Fold the dough over the filling from both sides, then tuck in the ends, pinching the seams together tightly to seal. Moisten the edges with a bit of water if needed for a stronger seal. Turn the loaf seam side down on a baking sheet lined with parchment.

With damp hands, smooth out the surface of the dough to prevent cracking during baking. Use your fingers to patch any weak spots, this crust must hold in all the steam and flavour for hours.

Place the pie in the oven and bake at 225°C for 30 minutes. This initial high heat sets the crust and starts sealing in the juices.

After 30 minutes, reduce the oven temperature to 125°C. Wrap the pie loosely in baking paper or foil to prevent drying out. Continue baking for 4–5 hours. This slow bake softens the bones (if using whole fish) and melds the filling into a tender, flavourful centre.

Resist slicing into the pie immediately, rest it for at least 20 minutes out of the oven. The filling continues to firm as it cools, making slicing easier and neater.

Serve warm in thick slices, ideally with a pat of butter and a glass of cold milk or buttermilk. Traditionally eaten as a standalone meal, it also pairs beautifully with pickled cucumber or beetroot for contrast. For presentation, slice diagonally and serve on wooden boards or rustic platters.