Meanwhile, bring a medium pot of water to a boil. Add the cauliflower florets to the pot and boil for 7 minutes or until very fork-tender. Strain off the water.
Add the boiled cauliflower florets, almond milk, cashews, lemon juice, nutritional yeast, sea salt, and black pepper to a high-speed blender (do not use a food processor).
Blend on high for 2 minutes or until completely smooth and creamy. Set within reach of the stove.
Heat the olive oil and garlic in a large sauté pan over low heat. Cook for 2 minutes, or until soft and fragrant.
Stir in the cauliflower sauce, increase heat to medium, and simmer for 3 minutes, or until hot and bubbly.
Turn off the heat, add the pasta to the pan, and toss to coat. If a slightly thinner sauce is desired, add more plant-based milk, one small splash at a time, to thin. (Note: If you add more milk, you'll need to increase the seasoning to accommodate.)
Taste and generously season with more sea salt and black pepper to taste.