Preheat oven to 200°C (400°F) and place a large sheet tray in the oven while it is preheating.

Using a pastry brush, brush the cut sides of the bread with 15ml (1 tablespoon) of the olive oil. Once oven is preheated, remove the sheet tray and place the bread - cut side down - on the preheated tray. Cover tightly with foil and bake for 10 minutes.

While the bread is in the oven, add the 3 cloves of sliced garlic to a small saucepan. Pour over remaining 45ml (3 tablespoons) of olive oil and set over medium-low heat. Cook the garlic in the oil, swirling frequently, until the garlic is fragrant and lightly toasted and golden brown - about 5 minutes.

While the garlic slices are cooking, grate the remaining 3 cloves of garlic into a small, heatproof bowl. Add the chilli flakes, if using, and the salt. Once the toasted garlic is finished, immediately pour the oil over the grated garlic mixture. Stir until well combined.

Remove the bread from the oven and remove the foil (set aside for later). Flip the bread over and evenly spoon the garlic and oil over the toasted bread halves. Cover the sheet tray with foil again and place in the oven for a further 5 minutes

Remove from the oven, top with parsley and slice into smaller pieces. Serve and enjoy.