For the sauce, melt 150 g butter over medium heat, bring to the boil and skim off the foam with a ladle. Wash the orange, rub dry and grate the peel thinly. Halve the orange and squeeze 1 half.
Wash the basil, dab dry and chop 3/4 of the leaves finely. Wash and peel the asparagus and cut off the woody ends. Bring plenty of water, some salt, sugar and 1 tablespoon of butter to the boil in a large pot.
Add the asparagus to the boiling water, cover and cook for 15-20 minutes. Wash salmon, dab dry and season with salt and pepper. Heat oil in a pan and fry the salmon slices for 4-5 minutes, turning them over.
Place the egg yolks, orange peel and white wine in a metal bowl and beat over a hot water bath until frothy. Add the butter drop by drop while stirring constantly. Add basil to the finished sauce and season with 1-2 tablespoons of orange juice, salt and pepper.
Remove the asparagus from the water and arrange on 4 plates. Pour hollandaise sauce over the asparagus and grill under the grill of the oven for 2-4 minutes until golden brown. Arrange salmon on the plates and garnish with basil.