1) Preheat the oven to 350°F with the oven rack in the middle. Lightly grease an 8 1/2" x 4 1/2" inch loaf pan.
2) Place the sugar, soft butter, salt, baking powder, and grated orange rind or orange oil in a mixing bowl. Beat with an electric mixer until fluffy.
3) Whisk together the flours, milled flax, and xanthan gum.
4) Beat the eggs into the butter mixture one at a time, scraping the bottom and sides of the bowl between additions.
5) Add the dry mixture about 1/3 cup at a time, alternating it with the orange juice.
6) Stir in the cranberries and nuts.
7) Scoop the batter into the prepared pan, mounding it in the center of the pan to create a dome shape. Sprinkle with coarse sparkling sugar, if desired.
8) Let the batter rest for 10 minutes.
9) Bake the bread for 58 to 68 minutes, until it's golden brown on the top. If you have a thermometer, the internal temperature should be 200°F or higher; see tip below.
10) Remove the bread from the oven, and allow it to rest in the pan for 15 minutes, then transfer it to a rack to cool completely. The bread is tender, and will slice with less crumbling after it's completely cool, about 4 hours.
Yield: 1 loaf.