Two things of interest in this scene:

1. The original script had Kay eating spaghetti, but it was deemed too messy in the close-up pictures, so they substituted lasagna instead.

2. The original script called for Michael's dialogue to be a lot more graphic (taken from the novel), but it was changed (obviously) for the filmed sequence:

(original scripted dialogue)

Mike: "Once upon a time, about 15 years ago, some people wanted to take over my father's olive oil business. They had Al Capone send some men in from Chicago to kill my father, and they almost did".

Kay: "Al Capone"!?!

Mike: "My father sent Luca Brasi after them. He tied the two Capone men hand and foot and stuffed small bath towels into their mouths. Then he took an ax, and chopped one man's feet off....."

Kay: "Michael"

Mike: "Then the legs at the knees....."

Kay: "Michael, you're trying to scare me....."

Mike: "Then the thighs where they joined the torso".

Kay: "Michael, I don't want to hear anymore...."

Mike: "Then Luca turned to the other man...."

Kay: "Michael, I love you".

Mike: "...who out of sheer teror had swallowed the bath towel in his mouth and suffocated".

Kay: "I never know when you're telling me the truth".

Mike: "I told you you wouldn't like him." (meaning Luca Brasi)