Peel and finely chop the onion. Peel garlic and chop finely. Wash fish, dab dry, cut skin side with a sharp knife 2x. Sprinkle with lemon juice and salt.
Clean and wash the cherry tomatoes. Prepare rice in boiling salted water according to package instructions. Meanwhile heat 1 tablespoon of oil in a pot, fry onion until translucent, add garlic and fry briefly.
Deglaze with 100 ml water, add the spinach, cover and heat over medium heat for about 16 minutes. Then bring to the boil 1x briefly and season with salt, pepper and nutmeg. In the meantime, dice butter and put it back in the fridge.
Pour the wine into a small saucepan and let it boil down until only the bottom of the saucepan is covered. Stir in the butter cubes bit by bit. Season with salt and pepper and keep warm. Meanwhile put flour and pepper in a deep plate, mix.
Turn the fish in it. Heat 2 tablespoons of oil in a large pan and fry the fish for 3-4 minutes on each side. Wash the thyme and shake dry. Add tomatoes and thyme to the frying fat 2 minutes before the end of the frying time.
Arrange fish with thyme and some sauce, rice, tomatoes and spinach on plates. Garnish with lemon slices. Serve the rest of the sauce separately.