Keto Sourdough Bread

Ingredients
1 ¼ cup fine almond flour
¼ cup psyllium husk powder
1/3 cup fine coconut flour
¼ cup flax seed powder
1 tsp baking powder
¾ tsp pink Himalayan salt
5 medium egg whites
1 medium egg
½ cup buttermilk, or keto buttermilk (½ cup unsweetened almond milk + ½ tbsp lemon juice)
3 tbsp raw apple cider vinegar
½ cup of warm water