Bring the stock, milk and 1/2 teaspoon salt to the boil in a saucepan. Slowly pour in polenta while stirring and bring to the boil. Let it swell for 6-8 minutes at low heat while stirring constantly. Spread hot mixture 1-1 1/2 cm thick to a rectangle (approx. 15 x 20 cm) on an oiled baking tray. Let it cool down for about 1 hour
Peel onion and garlic. Dice onion, chop garlic. Heat 2 tablespoons of olive oil in a saucepan, fry onion and garlic. Add deep-frozen spinach and about 100 ml water. Cover and allow to defrost over medium heat for about 15 minutes. Stir in between. Wash, drain and halve the tomatoes. Add 150 g tomatoes and cream cheese to the defrosted spinach, bring to the boil and simmer for 1-2 minutes. Season to taste with salt and pepper
Wash the salmon fillet if necessary, dab dry and cut into 4 pieces. Season salmon with salt and pepper and place in an ovenproof, wide dish. Put spinach on the fish. Mix the remaining tomatoes, 1 tablespoon of olive oil, a little salt and pepper. Arrange the tomatoes around the fish. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 15-20 minutes
Cut polenta into 4 pieces. Heat the fat in a large, coated pan and fry the polenta in 2 portions until golden brown. Divide the polenta into 4 plates and arrange a piece of fish on each plate. Pour the liquid into a pot with the tomatoes. Add cream and bring to the boil briefly. Season to taste with vinegar, some salt and pepper. Spread the melted tomatoes with the sauce on the plates
Waiting time approx. 35 minutes