Heat the oven to 400 degrees F. Place the cubes of butternut squash on a parchment-lined baking sheet and roast them for 40 minutes, tossing occasionally, until they are tender and browned. Of course, you can prepare the rest of the soup while this is happening. Shall we get to that?
Add two tablespoons of olive oil and two minced garlic cloves to a heavy bottomed sauce pot. Turn the heat to medium-low and stir the garlic, making sure it is covered with the oil.
As the oil warms, the garlic will begin to infuse it and it will become very aromatic. This method prevents the garlic from getting overcooked.
Now add in the 1/2 cup of chopped onion, 1/4 cup of chopped carrots, and 1/4 cup of chopped celery.
NOTE: This is a mirepoix: 2 parts onion, 1 part carrots, and 1 part celery. Typically used in French cooking, but with butter instead of oil.
Increase the heat to medium, add the 1/2 teaspoon of salt, and sweat the onions, carrots, and celery; these are known as aromatics. You’re going to cook this mixture about 5 minutes. What is happening here is you are removing the moisture from them, plus breaking down that cell structure, creating more intense flavors for the broth. The salt also helps pull out this moisture.
TIP: It is important to salt your food at the beginning of cooking. Salting at the start gives the salt the opportunity to fully penetrate all components of the dish. Plus, you’ll end up using less salt if you do it in the beginning versus the end.
Add in the sprig of fresh thyme, the Parmesan rind (unless you are vegan), and the four cups of broth and four cups of water. Bring to a boil and then reduce to a simmer, cooking for 30 minutes.
Strain the broth, removing the mirepoix, cheese rind, and the thyme sprig. This step is somewhat optional. Leaving the mirepoix in is a personal choice.
Transfer the broth back to the pot. Add the beans, roasted butternut squash, and bring to a boil.
Add in the sage leaf, quinoa, and kale, cover, and remove from heat. But remove the sage leaf before serving. This is great if you plan to serve the soup immediately.
TIP: Freezing soup can be a bit tricky. Items that don’t freeze well are pasta, last minute ingredients such as herbs, eggs, or cream. Most greens wont freeze well in soup as they can become very wilted and gross when reheating.
10. If you are planning to freeze the soup or to eat it for a greater part of the week, then I would only add in the kale just before serving. It won’t hold well in liquid for the week, or from being frozen.