In the bowl of a stand mixer, weigh the flour blend, sugar, baking powder, yeast, psyllium husks, and salt. Whisk to combine.

Add the softened or melted butter and mix on low using the dough hook or the beater blade. Add the egg and egg yolks, followed by milk. If using the dough hook, slowly add the liquid. Knead/mix on medium high for about 5 minutes. Dough will be wet and sticky and stretchy, which is completely normal.

Scrape the dough into the middle of the bowl (or into another bowl) and cover with plastic wrap. Refrigerate for at least 6 hours, preferably overnight (or up to 3 days).

On baking day, remove the dough from the fridge and knead it on a well-floured surface until smooth. Use plenty of extra flour as it will be very sticky. You can also place it in the freezer for 10 minutes to make it easier to work with if it's hot in your kitchen. Shape it into a loaf shape that will fit an 8½ by 4½ inch pan. Place it into a well-greased loaf pan. Cover with plastic wrap loosely (tucked in around the edges) and allow it to rise until doubled in size and cresting above the top of the pan by about one inch. This can take anywhere from 30 minutes to 2 hours, depending on your proofing area.

Preheat the oven to 175° C. Brush the top of the dough with egg wash gently. Bake for 30-35 minutes, or until a knife inserted all the way into the bread to the bottom comes out clean to nearly clean. You can also tell if it's done by feel. If the loaf feels relatively light for its size (picking up with pot holders in the pan), it's done. Internal temperature 87C

Remove the bread from the oven and immediately brush with melted butter. Place the loaf (in the pan) on a wire rack and cool for 10 minutes. Remove it from the pan and continue cooling until warm or room temperature before cutting.

This bread will keep, well wrapped, at room temperature for up to a week. For any longer storage, freeze whole or cut into slices.