Blend soaked cashews, 1/2 cup almond milk (or filtered water), lemon juice, and garlic together. If you haven't soaked your cashews in advance, you can quickly soften them by putting them in a heat-safe bowl and adding very hot (just under boiling) water to cover them. After 15 minutes, drain the water and your cashews should be ready to blend.
Blend in nutritional yeast and salt. Taste and add additional nutritional yeast and salt to taste. Add additional almond milk if too thick, a little at a time. Set aside.
In a large pan, heat a tablespoon of olive oil on medium heat. Add the brussels sprouts in a single layer and use a wooden spoon to get as many of the cut-sides down as possible. Don't stir for first 3-5 minutes so that the sprouts can sear.
Once sprouts are in pan, bring water to a boil in a large pot. Set aside.
While pasta is cooking and once sprouts have begun to sear, flip the sprouts. They should be a nice brown color. Add the rest of the olive oil, the mushrooms, and fresno chili to the sauté pan. Sauté on medium heat an additional 6-8 minutes, stirring occasionally, until the sprouts and mushrooms begin to feel tender.
Add garlic, shallot, and spinach. I recommend moving some of the ingredients to the sides of the pan so that the garlic and shallot can cook directly on the pan. Sauté everything additional 1-2 minutes until spinach is wilted and garlic is browned. Turn to low heat while you prepare the pasta, stirring occasionally.
Cook pasta according to instructions (usually 7-12 minutes)
Drain pasta and add it back to the pot it boiled in. Add the vegetables from the pan and stir in the cream sauce.
Serve with additional slices of lemon to squeeze on top (highly recommended) and salt and pepper to taste.