Possible Clues:

• Sauce of crushed basil leaves, pine nuts, garlic, Parmesan cheese, and olive oil
• Sauce devised in Genoa
• Fettuccine topper
• Bother reaching last of tomato sauce
• Basil-based sauce (though you can also use peas or garlic scapes)
• What you get when you blend the results of this puzzle's recipe instructions
• Genoese delicacy
• Basic sauce
• Bugger duck sauce!
• Think the world of