Wash the asparagus and cut off the woody ends. Peel white asparagus and cook in boiling salted water with 1 pinch of sugar for about 10 minutes. Add green asparagus and cook for about 5 minutes. Lift out the asparagus and drain well.
Measure out 100 ml cooking water and let it cool down a little.
Wash the salmon fillet, dab dry and cut into 4 equal pieces. Season with salt and pepper. Wash the basil, shake dry and pluck the leaves.
Mix sauce powder, cream and 100 ml cooking water. Bring to the boil while stirring continuously. Remove from the heat and fold in 50 g butter in pieces. Season to taste with lemon zest and juice.
Spread the asparagus in a greased casserole dish. Pour half the sauce over them. Put salmon on top. Put some basil leaves aside for garnishing, spread the rest on the salmon pieces. Cover with smoked salmon and pour the rest of the sauce over it.
Bake in the preheated oven (electric oven: 175 °C/circulating air: 150 °C/gas: level 2) for 20-25 minutes. Garnish with remaining basil leaves. Parsley potatoes taste good with it.
Drink tip: dry white wine, e.g. a Riesling.