Break cauliflower into flowerets. Cook in boiling water about 10 minutes, or until tender. Drain. Heat oil in a heavy pan or skillet. Add onions. Cook until tender. Add anchovies to oil. Heat and stir for 2 minutes. Add tomatoes. Cover and simmer about 20 minutes. Add nuts, currants, and cooked cauliflower. Add salt and pepper and mix well. Simmer over very low flame. Cook spaghetti according to directions. Top with sauce.