Preheat the oven to 350 F and place a rack in the center of the oven. In a medium mixing bowl add in the brown sugar, white sugar, salt, cinnamon, nutmeg, and all spice.
In a medium pot add in the butter and turn the heat onto medium low. We are browning the butter. First it will melt, then be loud and popping.
Then it’ll quiet down and foam – at this point you want to stir it and scrape the bottom of the pan. It will foam again and this time brown bits should rise to the top. At this point your butter is brown but not before!
Set your mixing bowl on the scale and zero it out. Pour the brown butter into the bowl it should weigh about 180-185 grams. Immediately pour oil into the bowl so the total weight becomes 225 grams. If you "mess this up" don't stress just pour 40 grams of oil into the bowl after the brown butter.
Whisk to combine and then add in the vanilla and three eggs. Whisk again before pouring in the apple cider and apple sauce.
Lastly add in the flour, baking soda, and baking powder. Whisk until just mixed.
Line two 8" metal round pans with parchment in the base. Pour half the batter into each pan, it should be about 630 grams of batter.
Bake both pans in the preheated over for 15 minutes. Then rotate 180 degrees and bake for another 10-15 minutes until a toothpick inserted in the center comes out clean.
Take the baked cakes out of the oven and let them cool in the pans for 15 minutes. Flip the semi cooled cakes out of their pans onto a wire cooling rack. Set them aside while prepping the cinnamon sugar. Don't leave to cool for more than 5-10 minutes.