Cut the leek by removing the top, dark green part. Cut it in half lengthwise and wash it under running water as you fumble with the leaves so the water can clean out any dirt.
Slice the pumpkin.
Mix the leek and pumpkin with the salt, pepper, bayleaves and plenty olive oil so they don't burn.
Take to a preheated oven at 200C for 40min-1 hour or until the pumpkin is soft. Check every 20min and give it a stir. Also add more olive oil if it seems dry.
Chop the herbs and mix with the lime juice and Dijon mustard.
Add salt and pepper to the chicken pieces and mix with the mustard.
Let marinade for at least 30min and a maximum of 24 hours.
Sear the chicken on a pan on high heat with a bit of olive oil. Then transfer to a baking dish.
Take to a preheated oven at 200C for 30-40min or until the juices are clear and it reaches 73C in the center (you can use a meat thermometer for this)