Peel the white asparagus, cut off the ends and cut the asparagus stalks diagonally into thin slices. Cut off the lower third of the green asparagus and cut it diagonally into fine slices.
Melt the butter over medium heat, add the white asparagus and cook for about 3 minutes. Add the green asparagus and sauté it briefly. Deglaze with the cream, add lemon juice, port wine, salt and pepper and let the whole thing reduce for about 4 - 5 minutes. The asparagus should still be crisp.
Fry the scallop in the heated oil, the core should still be translucent.
Put the ragout on a plate and serve the scallop on top.