Preheat your air fryer to 385 degrees so it’s ready to go once everything is assembled. While it’s heating, cut each slice of cinnamon raisin bread into small, even cubes so they soak evenly in the mixture.
In a large bowl, whisk together the milk, heavy cream, eggs, and vanilla until fully combined. Add the bread cubes to the bowl and gently stir to coat, making sure all the pieces are covered. Let the mixture sit for about 10 minutes so the bread can absorb the custard.
Divide the soaked bread mixture evenly into silicone muffin liners, filling each one about three-quarters full. This helps them cook evenly without overflowing.
In a small bowl, add the softened butter and use a fork to break it up. Mix in the flour, brown sugar, chopped pecans, sugar, and cinnamon until a crumbly topping forms. Sprinkle this mixture evenly over each muffin.
Place the filled muffin liners into the air fryer basket, working in batches if needed. Air fry at 385 degrees for 12–14 minutes, or until the tops are golden and the centers are set. Let them cool slightly before serving so they hold their shape.