Preheat oven to 425°F. Melt butter in a small saucepan over low heat. Add garlic and cover; set aside off heat.
Place broccoli in a large bowl and toss with olive oil, salt and pepper. Spread broccoli out in a single layer on 2 large rimmed baking sheets. Roast, stirring often, until softened and lightly browned on edges, 20 to 25 minutes.
Meanwhile, place pine nuts in a large skillet. Toast over medium heat, stirring and tossing often, until golden brown, 3 to 5 minutes. Transfer to a small bowl to cool.
Transfer broccoli to a large bowl and pour on butter and garlic mixture. Season with salt and pepper. Toss with pine nuts just before serving.