Preheat oven to 350 degrees F (175 degrees C). Line a loaf pan with parchment paper. Beat eggs in a bowl using an electric mixer on high until frothy, 1 to 2 minutes. Add butter and coconut oil; continue beating until smooth. Mix almond flour, baking powder, xanthan gum, and salt into egg mixture until dough is well mixed and very thick; transfer to the prepared loaf pan. Bake in the preheated oven until a skewer inserted in the center comes out clean, about 45 minutes