Peel the asparagus, cut off the ends, boil in salted water, adding 1 tbsp. l. butter, sugar and lemon juice. Boil the white asparagus first, 7 minutes, then add the green asparagus and cook all together for another 8 minutes. - until ready. Remove, dry, keep warm. Leave the broth. Wash lettuce, disassemble into leaves. Peel the grapefruit from the peel and films, divide into fillets. Cut strawberries into slices. Arrange the asparagus, lettuce, grapefruit and strawberries on plates. For dressing, mix 100 ml of hot asparagus broth with pear juice, grapefruit juice and raspberry vinegar. Pour in olive oil, salt and pepper. Dress the salad on plates with the resulting dressing and serve.