Preheat air fryer to 390 F (200C) while prepping your toast.
Using a fork, smush the butter into a really smooth paste. Add the sugar, cinnamon, vanilla, salt and black pepper if using. Mix to combine well.
Spread generously on one side of the bread. Place the bread into the basket of the air fryer, and repeat the same with another piece of bread - you’ll probably fit two bread pieces at once into the air fryer.
Air fryer 5 minute until bread is crispy and golden brown and bubbling. Repeat with the next two pieces of bread. Enjoy!
Making in advance: This is best enjoyed fresh, but you can prep the butter sugar mixture ahead of time, store it in the fridge, and bring it to room temperature to sfoten before spreading on the bread and air frying.Storing leftovers: Leftover cinnamon toast can be stored 1-2 days in the fridge and reheated in a warm oven, or microwaved (But it'll probably get a little soggy). This is best eaten fresh.Doubling the recipe: You can easily double or half the recipe. If doubling, just air fry in batches.