This recipe for a delicious pesto-like sauce is from Rose Gray and Ruth Rogers' The River Cafe Cookbook. I haven't tried making it directly from the recipe - I just used one bunch of cavalo nero for two people, and just added oil until it looked like a thinnish, rough pesto.

Remove the stalks of the cavalo nero leaves. Blanch the leaves in a generous amount of boiling salted water along with 2 cloves of garlic for a few minutes only. Drain well. put the blanched garlic and the cavolo nero into the food processor and pulse-chop to a fairly coarse puree. In the last couple of seconds, pour into the processor about 75 ml of the oil. This makes a fairly liquid, dark green puree. Crush the remaining garlic cloves with a teaspoon of salt and stir into the puree, along with a further 75 ml of olive oil. Season to taste with salt and pepper.

Meanwhile, cook the farfalle in a generous amount of boiling salted water, then drain thoroughly. Put the pasta into the sauce and stir until each piece is thickly coated. Pour in the remaining olive oil and serve with parmesan.

Serves 3-4.