Danish seeded rye bread (Rugbrød)

1. The evening before, pour the hot water over the rye grains and linseed in a bowl, cover and leave overnight at room temperature.

2. In a large bowl, mix the sourdough starter with the buttermilk, then add the rye flour, sunflower seeds, salt and the soaked grains with any remaining liquid; stir with a wooden spoon into a sticky, thick porridge-like dough (no kneading needed).

3. Oil a loaf tin of about 30×10 cm, pour in the dough, smooth it with a wet spoon and prick it a few times with a fork.

4. Cover and leave to rise in a warm place for 6-8 hours (or another night) until it has almost reached the rim of the tin.

5. Bake in an oven preheated to 180 °C for about 1 hour 30 minutes, until the inside reaches 98 °C or a skewer comes out clean.

6. Turn out onto a rack, wrap in a tea towel and leave to cool for at least 12 hours before slicing thinly.

Tip: Rugbrød is the cornerstone of Danish cooking: every smørrebrød is built on it, and Danes eat it almost every day. It's a heavy, moist, slightly sour bread - it isn't supposed to be airy. Patience is the key: if you cut it warm, the inside stays sticky. If you don't have a sourdough starter, you can make it with an active yeast pre-ferment, though it will be less sour.