Preheat oven (electric cooker: 220 °C/circulating air: 200 °C/gas: see manufacturer). Line a baking tray with baking paper. For the potatoes, wash the potatoes thoroughly and cut them into 3-4 mm thick slices with skin. Mix the potatoes and 3 tbsp. oil, season with salt and pepper. If necessary, fry briefly in portions in a grill pan. Then (or directly) place on the baking tray and bake in a hot oven for about 25 minutes.
For the salmon in the meantime rinse the fillet and dab dry and cut into 4 slices. Peel garlic and chop very finely. Mix with soy sauce and honey and coat the fish with it. Add the fish to the potatoes on the baking tray and cook the last 7 minutes.
For the salsa, clean, wash and finely dice the radishes. Wash the herbs and shake dry, pluck the leaves and chop them finely. Mix the radishes, herbs, lemon juice and 4 tbsp. oil, season with salt and pepper. Arrange potatoes and salmon. Serve with radish salsa.