Preheat oven to 400°F (200°C).
Halve spaghetti squash, drizzle cut sides with 1 tbsp olive oil, season with salt and pepper. Place cut-side up on a baking sheet and bake for 30-45 minutes, until tender.
Toss cauliflower florets with remaining 1 tbsp olive oil, chili powder, salt, and pepper. Roast on a separate baking sheet for 25-30 minutes, until lightly charred.
Make the sauce: In a blender, combine coconut milk, roasted cashews, lemon juice, nutritional yeast, smashed garlic, salt, and pepper. Blend until completely smooth and creamy.
Scrape the spaghetti squash into strands. Toss the squash strands with the creamy coconut cashew sauce.
Serve warm, topped with fresh herbs, a sprinkle of red pepper flakes, and optional garnishes.