Wash the potatoes and cook in boiling water for about 20 minutes. Rinse potatoes under cold water, drain, peel and cut into small pieces. Wash asparagus, cut off woody ends.
Halve the asparagus lengthwise and cut into pieces at an angle. Bring vinegar, stock, 1/2 tsp salt, pepper and 1 pinch of sugar to the boil. Add asparagus and simmer for about 3 minutes. Stir 3 tbsp. oil into the asparagus. Clean, wash, halve and slice the radishes.
Fold the asparagus mixture and radishes into the potatoes. Wash wild garlic, dab dry and cut into fine strips, possibly down to 1-2 leaves. Mix with ricotta. Wash the fish and dab dry thoroughly.
Cut the fish several times about 1/2 cm deep and season inside and outside with salt and pepper. Fill the ricotta mixture into the abdominal cavities. Line a baking tray with aluminium foil and oil. Put the fish on top.
Heat 4-5 tablespoons of oil in a small pot. Sprinkle trout with the oil and cook in the preheated oven (electric range: 200 °C/ convection oven: 175 °C/ gas: level 3) on the 2nd rack from above for 20-25 minutes.
Season salad again with salt and pepper. Cut remaining wild garlic leaves into strips. Remove the trout, arrange with potato and asparagus salad and drizzle with broth from the baking tray. Sprinkle trout with wild garlic if necessary.