Cook the cauliflower in a large pot of boiling water until tender, about 8-10 minutes. Drain and set aside.
In a pan, heat olive oil over medium heat and sauté the garlic until fragrant.
In a blender, combine cooked cauliflower, sautéed garlic, plant-based milk, nutritional yeast, olive oil, salt, and pepper. Blend until smooth.
Cook the pasta according to package instructions. Drain, reserving 1/2 cup of pasta water.
Toss the pasta with the cauliflower Alfredo sauce, adding reserved pasta water to adjust consistency if needed.
Serve immediately, garnished with fresh parsley if desired.