In a large mixing bowl, incorporate the milk, cream, eggs, vanilla, salt, and sugar.
Gently toss the bread cubes in the egg wash.
In a separate small bowl, break the butter into pea-size pieces (Using a fork or a pastry blender or your hands) and mix with brown sugar, cinnamon and flour to make the crumble.
Scoop half a cup of bread cubes into a silicone muffin liner. Top with the crumble.
Place muffins in the air fryer basket and cook at 350° for 15 minutes.
Let cool, dust with powder sugar, and glaze with maple syrup.