How to Make It
In the bowl of a standing mixer electric fitted with the whisk attachment, mix the cornstarch with the potato starch, rice flour, millet flour, flaxseed meal, rice protein powder, psyllium husk powder, baking powder, salt, xanthan gum, sugar, yeast, vitamin C powder, sunflower seeds, whole flaxseeds and sesame seeds.
Fit the mixer with the paddle attachment and with the machine at low speed, add the water, eggs and 2 tablespoons melted butter until combined. Increase the speed to medium and beat the dough for 3 minutes.
Butter a 10-by-5-inch loaf pan and sprinkle the sides with sesame seeds. Transfer the dough to the loaf pan and using an offset spatula, gently smooth the top. Cover the dough loosely with plastic wrap and let stand at room temperature until it domes over the edge of the pan, about 1 1/2 hours.
Place a pizza stone on the middle rack of the oven and preheat to 425º. Bake the bread for 15 minutes, then reduce the oven temperature to 350º and bake for 30 minutes longer.
Unmold the bread and bake directly on the pizza stone for 20 to 25 minutes longer, until the loaf is golden and a thermometer inserted in the center of the loaf measures 208º. Transfer the bread to a wire rack and let cool completely before cutting.