Preheat the oven to grill 220 degrees Celsius. Line a baking tray with baking paper.
Put the sourdough slices onto toast, stopping the cycle when it's about 80% done - the rest of the toasting will happen under the grill!
Using a pastry or basting brush, lightly brush oil over the top of each slice of toast.
Spoon and spread overtop of the toast the the pizza sauce. Top with the mozzarella cheese slices.
Place toast under the grill for five minutes or until the cheese has melted to your preference. Keep a close eye on the edges of your toast - as it's already part-toasted, it can quickly burn if left for too long!
Remove and add a few turns of the salt and pepper grinder and torn basil leaves.