Bring a medium saucepan of salted water to the boil for the pasta. Halve the leek lengthwise and rinse under running water to remove any hidden dirt. Thinly slice the leek, discarding any dark green stem. Peel the pumpkin. Cut the pumpkin and zucchini into bite-size chunks. Crush or finely chop the garlic.
Step 2 — Start sauce
Heat 1 tbs olive oil in a medium deep frypan over medium-high heat. Add the leek and pumpkin, season with salt and cook, stirring occasionally, for 5-6 mins until the vegetables are slightly softened.
Step 3 — Simmer sauce
Add the garlic to the pumpkin mixture and cook, stirring, for 1 min. Add the zucchini, three-quarters of the cream* and 1 tsp dijon mustard and bring to a simmer. Reduce the heat to low and cook, stirring occasionally, for 8-10 mins until slightly reduced and the pumpkin is tender. Taste, then season with salt and pepper.
Step 4 — Cook pasta and peas
While the sauce is simmering, cook the pasta in the pan of boiling water for 8 mins. Add the peas, return to the boil and cook for a further 2 mins or until the pasta is al dente. Drain.
Step 5 — Pan-fry chicken
ADD CHICKEN OPTION Meanwhile, put the chicken flat on a board, put your hand on top and halve horizontally into fillets, then thinly slice into strips. Heat 2 tsp olive oil in a medium frypan over medium-high heat. Cook the chicken, stirring, for 4-5 mins until golden and cooked through. Remove from the pan.
Step 6 — Finish pasta
Finely grate the parmesan. Finely chop the parsley, including the stems. Add the pasta, peas, chicken, half the parmesan and half the parsley to the sauce and stir to combine. Taste, then season with salt and pepper. Divide the pasta among bowls and scatter with the remaining parmesan and remaining parsley to serve.