Preheat the air fryer: Set it to 350°F (175°C). Preheating helps the sugar caramelize evenly.
Soften the butter: Let 2 tablespoons of butter sit out until spreadable.
If you’re in a rush, microwave it in 5-second bursts—don’t melt it.
Mix the cinnamon sugar: In a small bowl, combine 2 tablespoons granulated sugar with 1 teaspoon ground cinnamon and a tiny pinch of salt. Stir until uniform.
Make the spread: Mash the softened butter with the cinnamon sugar. Add 1/4 teaspoon vanilla extract if using.
You want a thick, even paste.
Prep the bread: Lay 2 slices of bread on a cutting board. Spread the cinnamon-butter mixture edge to edge on the top side only. Cover the surface fully to prevent burned edges.
Load the basket: Place the slices buttered-side up in the air fryer basket. Leave a little space between them so air can circulate.
Air fry: Cook for 4–6 minutes.
Start checking at minute 4. You’re looking for a bubbly, glossy top that turns lightly golden with a few deeper caramel spots.
Cool briefly: Let the toast rest for 1 minute. The topping will set into a delicate, crisp shell.
Serve: Slice diagonally if you like.
Enjoy plain, or add a light pinch of flaky salt or a drizzle of honey for extra contrast.