In a large pot over medium-high heat, combine milk, water, and salt and bring to a simmer. Add the pasta, reduce heat to low, and cook for two minutes. Stir in the cauliflower and cook, stirring often, until pasta is al dente (almost cooked through, but not totally soft!). Check your package instructions for timing guidelines, but be sure to taste the pasta as you go since it will cook a little differently in milk versus water.