How to Make It
Preheat oven to 350°F with racks in upper and lower thirds. Combine butter, garlic, and rosemary in a small saucepan over medium. Cook, stirring occasionally, until butter melts and garlic turns golden brown, about 3 minutes. Remove from heat and discard garlic and rosemary.
Place bread in a large bowl. Gradually pour melted butter over bread, tossing to coat. Season with salt and toss to combine. Divide bread between 2 rimmed baking sheets and arrange in a single layer. Bake until golden brown, 20 to 22 minutes, rotating sheets and stirring halfway through. Let cool completely on baking sheets. Store in an airtight container for up to 2 weeks.