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.
Combine the melted butter, brown sugar, maple syrup, pecans and sea salt in a small bowl.
Pour the melted butter mixture into a buttered bundt pan. Using a large spoon, spoon the batter on top of the butter mixture and then smooth it out with an offset spatula so it’s even in the pan. Bake for 45-50 minutes, or until golden brown and when a cake tester is inserted it comes out clean. Cool for 10 minutes, and then invert the cake out onto a serving plate. I like to serve this warm, but it can also be served at room temperature.