2 cups walnutsMake the walnut crema. Place 1 cup of the walnuts in a pot with the water and garlic. Boil for 10 minutes. Transfer mixture to a food processor, add oil and lemon juice and purée until smooth, adding another ¼-½ cup water to achieve a thick, creamy texture. Season to taste. Place in a small bowl and put to one side.
Roast the remaining walnuts on an oven tray at 180?C for 10 minutes. Boil trimmed asparagus in lightly salted water for 3 minutes, drain and cool in cold water. Drain. Either pan-fry asparagus in a little olive oil or roast at 220?C for 8-10 minutes until just starting to brown.
Spoon a little walnut crema on to 6 serving plates. Divide asparagus among plates, sprinkle with roasted walnuts and shavings of parmesan or pecorino. Serves 6