Preheat the oven to 350ºF. Line 18 muffin cups with paper liners.

With an electric mixer, beat the cream cheese and the powdered sugar until light and fluffy, about 3 minutes. Add in the egg white and the vanilla and beat to combine.

In another bowl, whisk together the flour, pumpkin pie spice, baking powder and salt. In a second bowl, combine the pumpkin puree, sugar, eggs, vegetable oil and vanilla. Add the flour to the pumpkin mixture and stir just until combined.

Put about 1 tablespoon of the pumpkin batter in each prepared cup. Add a dollop (about 2 teaspoons) of the cheesecake mixture on top of the pumpkin batter. Add another spoonful of pumpkin batter, dividing it evenly over the cheesecake filling, filling each cup about 2/3 full.

Bake the cupcakes until they are springy to the touch, about 25 minutes. Let cool completely.

To make the frosting, beat the egg whites and the brown sugar int eh bowl of an electric mixer to combine. Bring a small pot with about 1 inch of water to a simmer and place the mixer bowl over the top. Whisk the mixture until it registers 160ºF on an instant read thermometer.

Return the bowl to the mixer and beat until light and fluffy, then lower the speed and continue to beat until the frosting is at room temperature, about 5 minutes. Beat in the 1/2 teaspoon of vanilla.

Pipe the frosting on the cooled cupcakes.