Leeks are a fantastic vegetable in the winter time because they can be left in the ground until you're ready to eat them. They're a near essential in winter soups. Paired with a broth, a few other vegetables and a bit of cream to fill you up, leeks are sure to become a staple on your winter comfort food list.
What I don't like about leeks and particularly leeks in soups is that most recipes are only looking for the white and light green portion of the leek, discarding the rest. In fact, most things that require peeling and pitting and seeding and juicing seem wasteful to me. I like to repurpose. The good news is that you can salvage the dark green portions along with your other vegetable waste and turn it into a flavorful vegetable broth that will act as the base for those same soups.
Start with the dark green portion of your leek. Then chop both ends off of a large sweet onion, peel and save both the ends and the papery skin. Chop half of it. Remove the leafy tops and the bottom root ball of the celery. Crush 8 to 10 cloves of garlic.
After heating 2 tablespoons of olive oil in a large stockpot, add all of the vegetable scraps aside from the onion ends and skin and the celery root ball. We can add those later. Sauté the roughly chopped vegetables for 10 minutes until they sweat and soften up.