Heat up your air fryer to 350°F (175°C).

In a big bowl, mix together eggs, milk, and vanilla until it's all smooth.

Pop the butter in the microwave, melting it in 30-second intervals.

In another bowl, combine the cinnamon and sugar.

Dunk each brioche bun into the egg mix, letting them soak for 5-10 minutes.

Place the buns in the air fryer, making sure they're not overlapping. Air fry for 8-10 minutes.

Pour that melted butter all over the buns. Roll them in the cinnamon-sugar mix until they're fully coated.