2 1/2 cups (500g) dried green split peas, soaked overnight in cold water
1 tablespoon olive oil
30g unsalted butter
2 onions, finely chopped
1 carrot, finely chopped
2 celery stalks, finely chopped
2 smoked ham hocks
1 cup (250ml) dry white wine
1 cup (250ml) chicken or vegetable stock
2 teaspoons fresh thyme leaves
2 bay leaves
Grated zest of 1 lemon
150ml sour cream
1/4 cup flat-leaf parsley, plus extra to serve
8 mixed smoked sausages (such as cabanossi, Vienna frankfurts, kransky and bratwurst)
Rye bread, to serve
Drain soaked peas. Rinse and drain again.
Heat the oil and butter in a large, heavy-based saucepan over medium heat. Add onion, carrot and celery and cook, stirring, for 5 minutes or until softened. Add ham, peas, wine, stock, herbs and zest with 1.5 litres (6 cups) water. Bring to the boil over medium-high heat, skimming any foam that rises to the top. Reduce heat to low and simmer, partially covered, for 2 hours until ham and peas are tender, stirring occasionally to prevent catching and topping up with more water if it's becoming too thick. Remove ham hocks from the soup. Cool, then peel and shred meat, discarding skin and bone. Set aside.
Stir sour cream and parsley into soup. If you prefer a smoother soup, cool slightly then puree half in a blender. Return to pan with shredded ham and heat through.
Meanwhile, cook sausages in boiling water for 2-3 minutes to heat through. Drain well and transfer to a plate. Slice some of the sausages. Divide soup among bowls. Serve topped with sliced sausages and extra parsley, with remaining sausages and bread on the side.