In a large bowl, whisk together the dry ingredients: flour blend, buckwheat flour, dry milk, psyllium, sugar, baking powder, baking soda, yeast and salt.
In a second bowl, whisk together the wet ingredients: starter, ginger ale, eggs, olive oil and apple cider vinegar.
Pour the wet ingredients into the dry and mix until a thick, sticky dough forms with no dry spots. Let it rest 10 minutes so the psyllium can thicken it.
Shape the dough into a round loaf with wet hands, set it on a piece of parchment paper and score the top with a serrated knife. Cover and let it rise in a warm spot for 1 to 2 hours, until puffy.
About 45 minutes before baking, put a Dutch oven with its lid in the oven and heat to 450°F.
Lift the loaf by the parchment into the hot Dutch oven. Cover and bake 40 minutes, then remove the lid and bake 15 to 20 minutes more, until deep golden and the inside reaches about 205°F.
Cool on a rack for at least 1 hour before slicing.