Stir the cold sparkling wine, flour, starch and salt until smooth and chill. Peel asparagus and cut off woody ends. Cut in half lengthwise once. Simmer the asparagus covered in a little lightly salted water for about 15 minutes.
Drain and store the brew. Clean dandelions and soak in lukewarm water for about 5 minutes. Rinse cold and drain well. Mix vinegar, 3 tablespoons asparagus stock, salt and pepper. Add olive oil drop by drop.
Wash the basil and dab dry. Pluck leaves, arrange on plates with dandelion salad and marinate with vinaigrette. Heat the oil in a saucepan. Pull asparagus in portions through the pastry and fry in hot oil for 2-3 minutes until golden brown.
Drain some of it. Serve immediately on the salad.