Place the red lentils in a pan and cover with water. Bring to the boil then turn down the heat, cover and simmer for 15 - 20 minutes. Until the lentils are soft but still have a little bite. Drain and reserve until needed.

Place the pasta in a pan and cover with heavily salted water. Bring to the boil, cover and simmer for 10 - 15 minutes or until the pasta is aldente. Drain and reserve until needed.

When the lentils have around 10 minutes left - heat the olive oil in a large pan over a low to medium heat. Crush the garlic and add the chilli flakes and crushed garlic to the pan and cook for about 2-3 minutes. Then add the fresh rosemary and cook for a further minute. Finely dice the onion and leek, then add to the pan. Stir well to incorporate the oil evenly, and cook for around 5 minutes until soft.

Pour the cooked lentils over the onion and leek mixture. Stir to combine and cook for about 2 minutes, until the lentils warmed through. Thickly slice the greens and add to the pan along with the cooked pasta. Stir well to mix evenly, as you do so the spring greens should start to wilt. Remove from the heat and season with salt and pepper to taste.

Chop the walnuts loosely, then zest and juice the lemon. Sprinkle the zest and walnuts evenly over the pasta. Serve immediately with the lemon juice drizzled over the mixture to individual taste.