Preheat oven to 450 degrees.
Arrange cauliflower on baking pan.
In a small bowl, mix together the olive oil, salt, pepper, garlic, olives, lemon zest and lemon juice.
Spread oil mixture over cauliflower, turning cauliflower pieces to coat evenly.
Roast till tender, about 30 minutes; check after 15 minutes and turn pieces over to brown evenly.