Preheat oven to 425 °F (219 °C). Toss acorn squash rings with 1 tbsp vegetable oil on a baking sheet and season with salt and pepper. Roast until tender and slightly caramelized, about 15 to 20 minutes.
Peel and mince the garlic. Peel and finely dice the onion. Drain and rinse the cannellini beans. Zest the lemon. Finely chop the parsley leaves. Over a sink, squeeze any water out of the spinach with your hands.
Add the butter to a medium saucepan over medium-high heat. Add as much of the diced onion as you’d like, and the minced garlic and cook until onions are translucent, about 3 to 4 minutes.
Gently stir in the spinach, coconut milk, nutritional yeast, cannellini beans, 1/2 tsp salt, and 1/4 tsp pepper. Cover, lower heat, and simmer for an additional 5 minutes.
In a small bowl, whisk together maple syrup, nutmeg, and 1 tbsp lemon juice. Brush the roasted squash with the maple syrup mixture and return to the oven to cook until the glaze is sticky, an additional 3 to 5 minutes.
Taste the creamed spinach and add more salt and pepper if necessary.
Divide creamed spinach and cannellini beans between large plates and top with maple-glazed squash. Garnish with chopped parsley, lemon zest, and as much or as little Aleppo pepper flakes as you like.