Preheat oven to 350ºF and adjust the rack to the middle position. Melt butter in a large skillet over medium heat. Add onions and stir occasionally until golden brown and caramelized, about 20 minutes. Add sage and stir for about 30 seconds. Remove skillet from the heat. Add biscuit pieces. Whisk together egg, cream and chicken stock, then pour over biscuit mixture. Season with salt and pepper and stir until incorporated. Pour stuffing into a buttered 11 x 7-inch baking dish. Bake for 30 - 40 minutes, until golden brown.Preheat oven to 350 degrees F and adjust rack to middle position. Place almond flour, coconut flour, salt, baking soda and baking powder in the bowl of a food processor. Pulse 2-3 times to combine. Add butter and pulse, 8-10 times until mixture looks like wet sand with pea-size clumps of butter. Pour mixture into a mixing bowl and stir in the milk and water. The mixture should be tacky, but not loose or runny. If it's too loose, stir in a tablespoon more of almond flour.Using a 2-inch cookie scoop, scoop dough and place each dough mound on a baking sheet lined with parchment paper. Repeat with remaining dough. Using your fingers, press gently on the tops of the dough mounds to flatten them just a little. Bake for 20-25 minutes, until golden brown on the edges.Cool biscuits, cut each in half lengthwise and leave out on the counter overnight. (or toast in a 300 degree F oven for 15 minutes until dried out).