Preheat oven to 350 degrees F. Line baking sheets with parchment paper or use baking stones. Set aside.
In medium-sized bowl, whisk together dry ingredients–flour, baking powder & soda, salt, cinnamon, and ginger. Set aside.
In a large bowl attached to a stand mixer, mix together on low speed sugars, coconut oil, and pumpkin until combined. Add in eggs and vanilla until combined.
With mixer on low, slowly add dry ingredients to batter and mix until just combined.
Using a cookie scoop (whatever size you want–I used a medium one), scoop out dough on to cookie sheet and bake for 10-12 minutes or until tops feel done (or just slightly underbaked)when touched. Remove from oven and let cool on baking sheet for 5 minutes before transferrin to wire rack to cool completely.
Beat egg whites until stiff. (You know they’re stiff when bowl is inverted and whites do not fall out)
With mixer on, add vanilla, flour, milk, and 2 cups of confectioners’ sugar, scraping down sides of bowl as needed. Cream for 2 minutes. Add butter and remaining 2 cups of confectioners’ sugar and beat until fluffy.
When cakes are completely cool, scoop cream filling onto cakes (I used the same size cookie scoop that I did for the cakes), covering with other side to make a sandwich.