Place cockles in boiling water with 3 tablespoons of saltbush to cook until they open.
Meanwhile, heat cream, saltbush and mountain pepper in a saucepan and simmer until it thickens, stirringly continuously. Add white wine and lemon juice and simmer for a further minute before stirring through the chives.
Drain cockles, add to sauce and stir to coat.
Serve with crusty bread.