Preheat the oven to 350 degrees. Prepare your bundtlet pan by applying a layer of non-stick spray and sprinkling them with all-purpose flour. Remove any excess flour from the pans and make sure that each cavity is evenly coated to avoid sticking.

In the stand mixer bowl, cream the softened butter and the granulated sugar until they become lighter in color and have a fluffy appearance.

Add in the pumpkin spice, salt, baking powder, vanilla, milk, oil, pumpkin puree and egg whites.  Mix again until well combined.

Finally, incorporate the flour and thoroughly combine. Pause the mixer and scrape the edges as necessary, then mix once more. The mixture should not contain any bumps or lumps.

Using an ice cream scoop or small measuring cup, scoop out enough batter to fill each mini bundt cake cavity about ⅔-¾ full.  The dough will rise slightly during bake time.

Bake in the preheated oven for 14-16 minutes or until set and edges are just slightly browned.

Wait until the bundtlets have cooled down entirely before trying to take them out of the pan. When ready, carefully use a butter knife to help release the bundt cakes from the pan.

To make the frosting:  Mix together the softened butter and cream cheese in the bowl of a stand mixer.  Add in the vanilla and salt.  Finally, add in the powdered sugar and mix until smooth.  The mixture should be stiff peak consistency and creamy.

Transfer a few scoops of frosting to a pastry bag fitted with a large star tip and twist the end to keep the frosting contained.  Gently pipe a dollop of frosting on each bundlet.  Finally, using a sifter, sprinkle a handful of powdered sugar over each mini bundt cake.  Serve immediately.