[German] How to cook Herring salad

Ingredients
- 10 Matjes fillets (pickled herring)
- 200 g bottled or canned beetroot, drained, diced
- 2 white onions, finely diced
- 150 g roast beef, diced
- 250 g gherkins, diced
- 250 g peeled apple, diced
- ¼ cup (45 g) baby capers
- 2 eggs
- 125 ml (½ cup) vegetable oil
- 2 tbsp red wine vinegar
- black rye bread to serve