Place a steamer insert into a saucepan and fill with water to just below the bottom of the steamer. Cover and bring the water to a boil. Place cauliflower and garlic in steamer and steam until soft, 10 to 15 minutes.
Remove garlic cloves and smash with a fork; place smashed garlic with cauliflower into a pot.
Smash butter and chives into cauliflower and garlic with a fork or potato masher until smooth.
Stir light cream into smashed cauliflower mixture.
Sprinkle Parmesan-Reggiano cheese onto cauliflower mixture; season with salt and black pepper.
Cook the cauliflower mixture over low heat to absorb the cream and melt the butter, about 12 minutes.
