Peel the onions. Put the roast in a pot. Pour on enough water to cover the roast well. Add onions, bay leaves, juniper berries and peppercorns and bring to the boil. Cook over medium heat for about 1 1/2 hours.
In the meantime, for the bread crust, knead the baking mixture and 340 ml of lukewarm water with the dough hooks of the hand mixer. Cover and leave to rise for about 30 minutes. Remove the meat from the pot, drain well and let it cool down a little. Roll out the dough 1/2 cm thick on a floured work surface. Place the roast on top and brush with mustard. Moisten edges of dough with water and wrap ham in bread dough. Place the roast on a baking tray lined with baking paper, cover and leave to rest in a warm place for about 30 minutes. Bake in a preheated oven (electric cooker: 225 °C/ convection oven: 200 °C/ gas: level 4) for approx. 1 hour. Reduce the temperature after 10 minutes (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3). Wash herbs, shake dry and chop.
Place the roast on a baking tray lined with baking paper, cover and leave to rest in a warm place for about 30 minutes. Bake in a preheated oven (electric cooker: 225 °C/ convection oven: 200 °C/ gas: level 4) for approx. 1 hour. Reduce the temperature after 10 minutes (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3). Wash herbs, shake dry and chop. Puree sour cream, yoghurt, mayonnaise and herbs with a hand blender. Season to taste with salt and pepper. Cut the finished roast into slices and serve with sauce
30 minutes waiting time