Separate eggs. Mix egg yolk and cream cheese. Sift the baking powder over the mixture and stir in quickly. Beat egg whites and 1 pinch of salt until stiff. Fold the beaten egg white into the egg yolk mixture in portions.
Place the mixture with a tablespoon in 8 blobs on a baking tray lined with baking paper. Bake in a hot oven (electric cooker: 150 °C/circulating air: 125 °C/gas: see manufacturer) for about 25 minutes.
Peel onions and garlic. Finely dice 1 onion and garlic. Knead minced meat, mustard, diced onion and garlic. Season with about 1 tsp salt and 1⁄2 tsp pepper. Shape into 4 flat minced steaks. Heat oil in a large coated pan. Fry the steaks for 5-6 minutes on each side.
In the meantime, clean, wash and shake dry the salad leaves. Cut remaining onion into rings. Wash and slice the tomato. Cut gherkins into slices. Wash chives and cut into fine rolls.
Let the egg white breads cool down a little. Cover 4 loaves with lettuce, minced steak, gouda, tomato, gherkin, onion rings, lettuce cream and chives. Place the remaining bread on top.