Preheat the oven to 350ºF and adjust the rack to the middle position. Place the butter and sugar in the bowl of a standing mixer, and beat for 5 minutes on medium-high until light and fluffy. Scrape the sides of the bowl and add the eggs one at a time with the mixer on low.
In a separate bowl, whisk together the almond flour, arrowroot, coconut flour, baking powder and sea salt. In a separate measuring cup, combine the whole milk and extracts.
With the mixer on low, add 1/3 of the flour mixture then 1/3 of the milk mixture. Continue to alternate between dry and wet ingredients until all ingredients have been added and combined.
Pour the batter into a buttered 1 1/2 quart loaf pan. Bake for 60 minutes, or until golden brown. Cool for 10 minutes, and then invert the cake out onto a serving plate. Cool completely. Serve.
Notes
I only test the recipes on my site with the listed ingredients and measurements. If you would like to try a substitution, you are welcome to share what you used and how it turned out in the comments below. Thanks!