Preheat oven to 350 degrees. Line the bottom of an 8 1/2 x 4 1/2 inch loaf pan with parchment paper and lightly spray the sides of the pan with cooking spray
In a large mixing bowl whisk together almond flour, psyllium husk powder, whey protein powder, xanthan gum, salt, baking powder and cream of tartar until just combined.
Add instant yeast and whisk until fully combined and no lumps are in the flour. Set the bowl aside
In a large mixer bowl combine eggs, oil, honey, milk, apple cider vinegar. Beat on low 10 to combine the ingredients then on medium for 3 minutes or until frothy.
Add half of the dry ingredients . Beat on medium for 10 seconds or until combined. Add sour cream and beat on medium 10 seconds or until combined
Scrape down sides and add the remaining dry ingredients. Beat on medium for 20 seconds or until fully combined and smooth.
Scrape down sides and push all the dough to the center of the bowl. The dough will be thick, wet and sticky
Scrape the dough into the prepared loaf pan and use a damp spatula to spread the dough evenly across the loaf pan
Cover pan loosely with lightly sprayed plastic wrap. Then lightly cover the pan with a clean kitchen towel. This helps create a draft free area for the dough to rise
Place the dough in a warm draft free area and let it rise 1 hour or until it has risen just above the edge of the pan. See notes of how to create a "proof box" for the dough to rise in
Once the dough has risen uncover and bake at 350 for 35-40 minutes or until a tester comes out clean
Once the bread is baked let it cool in the pan for 10 minutes to let the ingredients lock in. After the bread has set transfer the bread to a wire rack to cool completely before slicing
For a taller loaf bake the bread in a 7 x 3 1/2 inch loaf pan. This will be a taller loaf but it will be a bout an inch shorter.