Peel the potatoes and parsnips, and grate them into a large bowl. Chop the spring onions and chervil and add them, season with salt and pepper. Mix thoroughly, adding 50 ml olive oil.
Cook rösti in two batches. Heat large frying pan with 25 ml of the oil. Press half of the rösti mixture into the hot pan in a flat layer.
Cook on moderately high until the bottom crisps up, then turn it over on to the hot baking sheet. Repeat with the rest of the mixture.
Oil the haddock fillets and put them on to another baking sheet.
Put both sheets into the oven for 10 minutes (rösti on the top where it's hotter - check it after 5 minutes).
Meantime, crush the garlic and cook it in 10 ml of the olive oil until it begins to soften. Add spinach, stir until it has wilted completely. Press out the liquid that has formed while cooking, season and keep warm.
Poach the eggs in water and vinegar - aim for a runny yolk.
To serve, cut a wedge of the rösti, crown it with the spinach, haddock and on the top the poached egg.