Starting at the top, with a very sharp knife, cut down into each avocado until you hit the pit. Cut completely around the avocado, top to bottom, touching the pit the entire time.

Pull the two halves of the avocado apart and remove the pit with a spoon.

Use the spoon to scoop the avocado out of the skin. (Some people like to score the avocado with a knife before scooping.) Make sure to gently scrap the skin to get the dark, creamy "good stuff."

Place 2/3 to 3/4 of the softest avocados in a mixing bowl. Using a fork, roughly mash them.

Place the remaining firmest avocados on a cutting board or plate and chop into 1/4 to 1/2-inch pieces. Add these to the mashed avocado in the bowl and mix well.

Stir guacamole oil into avocado.

Add lemon juice, salt, tomato and onion. Mix gently but well.

Taste. Add more salt, to taste, if needed.