Drain the tuna and capers. Peel and chop the onion. Wash parsley, shake dry and chop. Tuna, 2⁄3 Puree the capers, onion, parsley and sour cream with a hand blender. Season to taste with salt and pepper.
Clean, wash and finely dice the peppers. Stir the remaining capers into the tuna cream. Cut out approx. 18 circles (approx. 5 cm Ø) each from white bread and cold cuts.
Half of the sandwiches are topped with roast beef, the others with turkey breast. Pour the cream into a piping bag with perforated spout. Spray about 3⁄4 of the cream on half of the loaves. Place the rest of the sandwiches on top.
Garnish with rest of cream and caper apples.