Prepare and cook dried peas according to on-pack instructions. Drain and set aside.
Heat olive oil in a large saucepan over medium-low heat. Add leek and cook covered, stirring occasionally, for 8 minutes or until soft. Add garlic and cook for 1 minute.
Increase heat and add potatoes. Stir to coat. Add stock, salt and 2 cups water. Cover and bring to boil. Reduce heat to simmer, partially covered, for 20 minutes or until potato is tender. Add prepared and cooked peas and turn off heat.
To prepare prosciutto, preheat oven to 200°C. Place slices on a tray lined with baking paper. Cover slices with a similar size tray to prevent curling. Bake for 10 minutes or until crisped. Cool and crumble into shards.
Puree soup with a stick blender until smooth. Serve with a drizzle of cream and sprinkle with prosciutto and chopped fresh chives.