Wash the spinach and drain well. Peel shallots and garlic. Finely dice the shallots. Wash lemon hot, squeeze half of it, cut the other half into slices. Wash fish, dab dry and cut into 8 pieces. Wash skin several times with a s
For the polenta, bring cream, milk and 700 ml water to the boil. Add about 1 teaspoon of salt. Add polenta while stirring and stir for 4-5 minutes at low heat. Then cover and let it swell for about 15 minutes on the switched off hotplate.
Heat 1 tablespoon of oil in a wide saucepan. Sauté the shallots until translucent. Sprinkle with 1 tablespoon of sugar and deglaze with vinegar. Add the spinach and let it collapse. Season with salt and pepper. Fold the spinach into the polenta. Keep warm.
Season fish with salt and pepper. Heat 2 tablespoons of oil in a coated frying pan. Sauté the fish in it on the skin side for about 2 minutes. Add garlic and lemon slices, turn the fish and fry for approx. 3 minutes. Keep warm.
In the meantime, melt butter for the lightning sauce. Puree the egg yolks, crème fraîche, a little salt and 2 tbsp. lemon juice in a tall, narrow beaker with a hand blender until smooth, slowly pouring butter into the egg yolk mixture. Season the sauce with salt and lemon juice. Arrange polenta, fish and sauce on plates. Sprinkle with oregano as desired.