Preheat your oven to 375°F/190°C (170°C fan oven), and line a rimmed baking sheet with parchment paper.
Slice the baguette or bread into thin slices, about 1/2 inch thick.
Brush each slice with olive oil on both sides.
Arrange the slices on a baking sheet and bake for 8-10 minutes, or until lightly golden brown and crispy.
Remove from the oven, sprinkle with flaky sea salt and allow to cool.
Serve the crostini as is or topped with your favorite toppings, such as tomato bruschetta, cheese and cured meats, hummus and vegetables, or any other toppings of your choice.
Notes
Choose bread that is firm and does not fall apart or crumble as you slice it.
1/2-inch slices are perfect for crostini. Any thicker than that and they won't get crispy all the way through.
If you're cooking outside, try grilling crostini! Preheat the grill to 375°F/190°C, and add the sliced bread right to the grill grates, over indirect heat.
To make garlic crostini, rub a peeled clove of garlic over the warm, crispy bread right after you pull it out of the oven.
To Store: Keep leftovers in a sealed container at room temperature for up to 5 days. You can also freeze the crostini for up to 1 month.