When pasta is done, drain noodles, let cool for a few minutes and toss them with the pesto in a large bowl or pasta cooking pot. Toss in tomato, if using, and season with additonal salt and pepper. Sever warm or chilled. Serves 2 to 4.
Variation- For a cheese version, add 1/4 cup soy or dairy parmesan cheese and reduce salt ot 1/4 tsp or less.