Preheat oven to 350 degrees.
Arrange bread slices on parchment paper placed upon large rimmed baking sheets.
Brush both sides 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.
Top crostini with desired toppings, and serve.