Heat the olive oil in a large pot over medium heat. Add the cauliflower and cashews and saute for 4 minutes until lightly browned. Add the garlic and cook for 1 to 2 minutes until fragrant. Add the vegetable broth, onion powder, black pepper, nutmeg and 1/2 teaspoon kosher salt. Bring to a simmer, then cover and cook 6 to 7 minutes on medium high heat until the cauliflower is tender when pierced with a fork.
Carefully transfer the contents to a blender and add the remaining 1/2 teaspoon kosher salt and 1/4 teaspoon more black pepper. Blend on high until a smooth sauce forms. Use about 5 cups on 1 pound pasta (1 cup will be left over).