Clean and wash the zucchini and carrots and cut them lengthwise into thin slices with a peeler or on a slicer. Peel and finely dice the shallots. Wash the dill, dab dry and cut finely, except for the stems.
Heat the fat in a small pot and sauté the shallots in it. Add flour and sauté briefly. Add stock and milk while stirring, bring to the boil and simmer for about 5 minutes while stirring.
Stir mustard and dill, except for something to sprinkle, into the sauce and season to taste with honey, salt and pepper. Keep warm. For the stock, put 1/2 litre of water, white wine, lemon juice and 2 lemon slices, dill stalks, 1 teaspoon of salt and peppercorns in a large deep pan or saucepan and bring to the boil.
Wash the fish fillet, dab dry and cut into 8 pieces/tranches. Put the fish fillet into the stock and let it simmer covered at low heat for 8-10 minutes. Put vegetables in boiling salted water and cook for 1-2 minutes.
Drain the vegetables and arrange with the fish slices on 4 deep plates. Spread a little sauce over them and serve immediately, garnished and sprinkled with remaining lemon slices and dill. Remaining sauce extra is enough.
Potatoes or rice taste good with it.