Select avocados that yield to gentle pressure. Most avocados darken when ripe. Also, stem will "pop" out easily on a ripe avocado. Cut avocados in half and remove large seed. Scoop out avocados into a mixing bowl and mash with a fork to desired consistency (you may want to leave chunky). Add one avocado seed to the mixture. Enzymes from the seed will help keep avocados from darkening. Add lemon juice, diced green onions, salt, Tabasco, diced tomatoes and chopped cilentro. Blend thoroughly. The cilentro is the "magic" ingredient which give guacamole its authentic Mexican flavor. Serve with your favorite chips or add as a topping to burgers or tacos. Refrigerate to allow flavors to marinate if you wish. Delicious! Serves 4-6 party people. Enjoy!