Add the gluten-free flour blend, instant yeast, and salt to the bowl of your stand mixer fitted with a dough hook.
Heat water to about 110°F using a meat thermometer. Water temperature matters—aim for warm, not hot, to give the yeast the best chance to do its job.
Begin mixing on low speed and gradually pour in the warm water, egg, egg whites, olive oil, and sweetener. Scrape down the sides as needed.
Once all ingredients are added, turn the mixer up to medium and knead the dough for about 5 minutes until it forms a smooth, uniform texture.
Brush a 9×5-inch loaf pan with oil, transfer the dough into it, and gently smooth out the surface. Use a spatula to gently level out the dough’s surface before letting it rise.
Cover the loaf pan loosely with a clean towel and place it somewhere warm to rise for 45 minutes. It won’t double but should puff up noticeably.
Toward the end of the rising period, begin preheating your oven to 375°F so it’s ready to go.
Bake the bread uncovered at 375°F for 30 minutes, then reduce heat to 350°F and bake an additional 30–35 minutes.
The bread is done when the internal temperature reaches 210°F—check with a thermometer for accuracy.
Cool in the pan for 15 minutes, then transfer to a wire rack to cool fully before slicing.