Cut off pointed end of garlic bulb. Place on a piece of aluminum foil, and coat generously with cooking spray. Fold foil to seal. Bake at 350° for 1 hour or until garlic is tender. Remove garlic from oven, and let cool. Squeeze pulp from garlic bulb, and mash with a fork until smooth. Set aside.
Meanwhile, slice kale leaves into 1/4" strips. Heat olive oil in a large Dutch oven over medium heat. Gradually add kale, and cook 12 minutes or until kale wilts, stirring often. Add broth. Reduce heat to low; cover and simmer 20 to 25 minutes or until greens are tender and liquid evaporates. Stir in garlic, salt, and pepper.
Make Ahead: Roast garlic, and trim and slice kale up to 2 days ahead. Chill in separate zip-top plastic bags.