To start, preheat your oven to 350°F. First, prep all of the vegetables by chopping the carrots, celery, celery leaves, zucchini, red onion, bell pepper into small pieces and mincing the garlic. Also, remove the stems from the bunch of kale and any thick stems of the spinachSet these all aside (I placed them all in one bowl to keep things organized), and heat up the tablespoon of olive oil on a large saucepan over medium heat.
Add in all of the vegetables to the saucepan after allowing the olive oil to heat up for about a minute. Sauté the vegetables for 3-5 minutes whilst stirring once every 30 seconds, or until the onion and celery have started to become translucent. The vegetables should have started to release moisture as well. Turn up the heat to medium-high and add in 1 ½ cup of the vegetable stock to the saucepan along with the rosemary, cumin, coriander, and chili powder, stirring so that all the ingredients get combined and that the vegetables are cooking evenly.
Once the vegetable broth has reached a slow boil, add in the 1/4 of quinoa and vegan ground 'meat', and stir to combine. Lower the heat to a medium-low simmer, and leave the mixture partially covered. Cook for 2 minutes shorter than the recommended cooking time of the quinoa (I cooked mine for 10 minutes and the recommended cooking time was between 10 and 15 minutes), pausing to stir once every couple of minutes.
Meanwhile, slice the kale leaves that have been removed from the stem into thin ribbons. Roughly chop up the spinach and basil if using as well. Once the quinoa has finished cooking, add in the last ½ cup of vegetable broth as well as the ½ cup of frozen peas, and turn up the heat to bring the mixture to a boil again. Cook everything on medium-high, uncovered, for several minutes, making sure to stir every couple seconds for another 5 minutes. The stuffing mix should be moist but not have too much liquid in it. Then, add in the kale, spinach and basil, and stir this in, cooking everything together for another 3-5 minutes. Once the stuffing is done and the greens are bright green and wilted, turn off the heat, and set the saucepan aside.
With a spoon, remove the middle part of the halved roasted butternut squash, leaving about an inch of the flesh closest to the outside of the squash. On a cutting board, chop up the removed butternut squash into small ½ inch cubes, and add it into the stuffing mixture, mixing it to combine. Using a spoon, scoop the quinoa and vegetable stuffing into the hollowed out centers of the butternut squash halves. There should be enough stuffing in each of the squash halves to create a little mountain, but there will likely be extra stuffing that you can serve as a side-dish.
Bake the stuffed squashes in the preheated oven for 22-25 minutes, or until the stuffing on top of the squash looks nice and crisp. Remove from the heat and enjoy warm with a side of cranberry sauce and maybe some of that extra quinoa stuffing mix!