Preheat oven to 350 degrees. Arrange baguette slices in a single layer on a rimmed baking sheet.
Brush the slices evenly with olive oil. Bake until lightly toasted, about 15 minutes.
Video
Notes
Baguette: I recommend using a crusty French baguette, but a fluffier Italian baguette will work, too.
Olive oil: 4 tablespoons butter may be substituted for the olive oil.
Yield: 1 (1-pound) baguette will yield about 20 slices of baguette (depending on how thick you cut them).
Storage: Store cut, un-toasted baguette slices in a plastic bag at room temperature for up to 3 days or freeze for up to 3 months. Thaw overnight at room temperature before brushing with olive oil and toasting.
Make ahead: Toast the crostini up to 3 hours ahead and store covered at room temperature.
Garlic twist: For a hint of garlic flavor (especially delicious with bruschetta), gently rub one side of each cooled crostini with a clove of peeled garlic (plan on 2 cloves per baguette).