Wash the maties, dab dry and dice finely. Peel and finely dice the onion. Drain the capers. Mix the maties, capers and diced onion and season with lemon juice and pepper.
Quarter the pumpernickel slices and cover with the matie starter. Clean and wash the salad and distribute it on 4 plates. Place the matie snacks on top and garnish with tomato and parsley.