Remove the rind from the cheese slices. Peel the pineapple and remove the stalk in the middle. Pineapple and cut into 16 thin slices. Mix together the barbecue sauce and sour cream. Season with a little salt.
Toast the white bread slices until golden brown.
Preheat the oven (electric stove: 200 ° C / convection: 175 ° C / gas: level 3).
If necessary, cover the rump steaks with cling film and plate carefully (approx. 4 mm thick). Heat 1 tablespoon of oil in a pan. Sear the rump steaks on each side for only 20 seconds. Then season with fleur de sel and black pepper from the mill.
Brush each slice of toast with 2 teaspoons of the barbecue sour cream sauce and top with 1 steak, 2 slices of pineapple and 1 slice of cheese. Bake in the hot oven for 5 minutes until the cheese has melted golden yellow.