Preheat oven to 350 degrees. Place bread slices on 2 rimmed baking sheets. Brush both sides of slices with oil, and season with salt and pepper.
Bake until golden, 15 to 20 minutes, rotating sheets halfway through (if undersides are not browning, turn crostini over once during baking). Let cool on baking sheets.
Crostini can be made 2 hours ahead.