1. Heat oven to 325 degree F. Wrap garlic tightly in foil and roast until soft, 1 hour. Let cool thoroughly. Carefully peel garlic out of paper husks, trying to keep cloves as whole as possible. Slice 8 of the largest cloves into thirds lengthwise. Set aside. Transfer remaining garlic cloves, cream cheese, green onion, lemon juice, thyme, oregano, rosemary, and salt to a food processor. Pulse until smooth, 1 to 2 minutes. Transfer to a bowl and refrigerate until ready to use.
2. Heat broiler. Cut one bread slice into 8 triangles by cutting bread diagonally into quarters, then cutting each quarter in half to form 8 triangles. Repeat with remaining bread slices. Transfer slices to a broiler pan and broil about 1 minute per side (watch carefully so they don't burn). To assemble, spread 1 teaspoon of herbed cream cheese evenly over each toast, then top with a slice of garlic and a parsley leaf. Sprinkle with pepper, if desired. Makes 24 canapes.