Remove most cauliflower leaves, rinse, and cut the head in two.
Boil 4 to 5 quarts of water, add the cauliflower, and cook until tender but not mushy, about 25 to 30 minutes. Drain and set aside.
Bring water to a lively simmer in a saucepan (to use as a double boiler).
In a medium saute pan, cook the oil and chopped garlic over medium heat until the garlic turns light golden brown.
Take the pan off the burner, set it over the simmering water, add anchovies, and stir and mash them against the pan until they dissolve as much as possible into a paste. Put the pan back on the burner over medium heat and cook about 30 seconds, stirring.
Add the drained cauliflower, quickly breaking it up into small pieces. Turn it in the oil, mashing some with the spoon.
Add chili pepper and salt, raise the heat, and cook a few minutes more, stirring frequently. Toss with hot drained pasta, add parsley, toss once or twice again, and serve.