Tallarines verdes

Step 1: Bring 4 litres of water to the boil in a large pot and add 1 tbsp salt. Set a bowl of iced water beside the stove.

Step 2: Drop 2 ⅞ oz basil leaves and 5 ½ oz spinach leaves into the boiling water for 20 seconds, just until they wilt and turn vivid green, then lift them straight into the iced water with a slotted spoon. Keep the pot boiling for the pasta.

Step 3: Heat 3 tbsp vegetable oil in a small frying pan over a medium-low heat and cook 1 onion and 2 cloves garlic, stirring, until soft and translucent but not coloured.

Step 4: Squeeze the cold leaves firmly to remove most of the water. Put them in a blender with the onion mixture, 5 ½ oz queso fresco, ¾ cup evaporated milk, 1 oz walnuts and ½ tsp black pepper, and blend until completely smooth and pale green, about 1 minute.

Step 5: Cook 14 oz spaghetti in the boiling water until just al dente, 1 minute less than the packet says. Scoop out a mugful of the cooking water before draining.

Step 6: Return the drained pasta to the pot over a low heat, pour in the green sauce and toss for 1–2 minutes, adding splashes of pasta water until the sauce coats each strand and looks glossy rather than thick. Don't let it boil, or the cheese can turn grainy.

Step 7: Taste, add salt if needed and serve at once in warm bowls.