Refrigerate bagels at least 1 hour for easier slicing. Preheat oven to 325 degrees. To slice bagel, place bagel flat on cutting board. With a serrated knife, cut bagel in half vertically. Place halves on cutting board, cut side down. Cut halves into thin slices, about 1/4 inch thick. Repeat with remaining bagels. Place slices on ungreased baking sheets.

In a small bowl, blend butter with garlic or onion salt. Spread over tops of slices and bake 15-20 minutes or until lightly browned. Cool on a wire rack. Store in airtight container.