Last week my college gave me this recipe and a little jar with bread starter. You can make it your self, but for me it was easier and faster. Starter is just flour and water, natural yeast, which you need to grow at a room temperature.
For one loaf you need:
150g of active Rye flour starter
300g warm water
400g plane wheat flour (type 650 or 550, one part can be replaced with wholegrain flour. I used plane flour from Lidl)
100g Rye flour (type 720)
1,5 tsp salt
1 tsp of dry yeast
1. If you had your starter in a fridge take it off before bed time. Feed it with 100g of Rye flour and 100 warm water. Set aside in a bigger bowl. Leave it over night.
2. In the morning put all ingredients in a bowl with starter and mix with cake hook 7-8 min or longer if you will be using your hands. It should be loose and sticky. Cover bowl with a cloth and leave aside for about 15min to rest and to be elastic. Leave for 2-2,5h to rise in a warm place, then form and put into baking tray (mine is 13x28x5,5cm)
3. Allow to grow double size.
4. Bake at 230C preheated oven for about 40-45 min, let the skin become brown and crispy. Then leave it cool.