Preheat the oven to 350 F. Spray a rimmed baking sheet (half sheet pan (approximately 13" x 18", and 1" deep sides) with baking spray, then line it with parchment paper. Set aside until ready to use.
Whisk the dry ingredients together in a large bowl. (Flour, baking powder, baking soda, cinnamon, ginger, nutmeg, salt.) Set aside.
In a separate large bowl, whisk the eggs and sugar together. Add the oil, greek yogurt, and vanilla. Whisk until everything is fully blended.
Slowly add the wet ingredients to the bowl of dry ingredients, whisking as you combine. Once fully blended, use a spatula fold in the grated carrots. Be careful not to overmix.
Pour the mixture into the prepared rimmed baking sheet, and bake at 350 for 30-35 minutes, until the center is set and the cake is fully baked through.
Remove from the oven, and allow the cake to cool in the pan for about 20 minutes. Transfer the cake to a wire baking rack, and cool another 20 minutes.
Once the cake is completely cooled, use a 1 1/2" biscuit cutter to cut circles out of the cake.
Spread a layer of cream cheese frosting on top of each tiny cake, and set the un-frosted side of one cake on top of the frosted part of another cake, to create two "layers" with frosting in between them.
Top the "layered" cake with grated cinnamon, chopped walnuts, or sprinkles. Enjoy immediately, or refrigerate in a tightly sealed container for up to a week!
You can use whichever size biscuit cutter you like! You could also use cookie cutters!