Prepare the garlic butter: Place 30g butter into a microwave-safe bowl and microwave for 30 seconds to 1 minute until fully melted. Add 1tbsp minced garlic and 1/4tsp salt, then stir until well combined.
Prepare the cheese layer: Place 1 slice white sandwich bread on a board and spread 1–1½ cups shredded mozzarella cheese evenly over the bread.
Assemble the sandwich: Place 1 slice white sandwich bread on top of the 1–1½ cups shredded mozzarella cheese layer and press gently so the bread sticks slightly to the cheese.
Cut into a 9-square grid: Using a sharp knife, cut the sandwich into a 3 × 3 grid to create 9 squares. Cut through the top slice and the cheese layer and lightly score the bottom slice, but do not cut all the way through the bottom slice of bread.
Spread the garlic butter on top: Spread the prepared 30g butter, 1tbsp minced garlic and 1/4tsp salt garlic butter mixture evenly over the top slice of bread, allowing some butter to run into the cut lines.
Air fry the toast: Place the prepared toast into the air fryer basket and cook at 180°C for 5 minutes until golden and the 1–1½ cups shredded mozzarella cheese inside is melted.
Cool slightly and serve: Remove the toast from the air fryer and rest for 1–2 minutes. Sprinkle 1/2 tsp parsley for garnish, and then pull apart the squares and serve.