1 cup brown rice flour
3/4 cup sorghum flour
1 1/2 cups tapioca starch
1 Tbsp xanthan gum
2 teaspoons coarse salt
1 1/3 cups water (slightly warm, especially if your rising area is cold, but not so warm that you kill the yeast -- just comfortably warm)
1 Tbsp active dry yeast
1 Tbsp plus 1 tsp neutral oil, like canola
1 Tbsp sugar
1/3 cup toasted pumpkin seeds
1/4 cup whole flax seeds
3 Tbsp toasted sesame seeds
1 egg, beaten with 1 small splash water (aka "the egg wash")
3 Tbsp raw pumpkin seeds
2 Tbsp whole flax seeds
2 Tbsp sesame seeds
Mix together the rice flour, sorghum flour, tapioca starch, xanthan gum, and salt. Set aside. In the bowl of a mixer (or another large bowl), pour the water and sprinkle the yeast over it. Let sit for a few minutes to allow the yeast to soften. Add the eggs, oil and sugar, and mix thoroughly. Add the gf flour mixture, and mix thoroughly to combine. If you're using a mixer, use the paddle rather than the dough hook. Continue to mix together until the dough is well-combined and smooth. The dough will not seem like a traditional bread dough -- it's somewhere between a cake batter and smooth mashed potatoes. Add the pumpkin, flax, and sesame seeds, and stir to combine.
When the dough is mixed, place it in a lightly-oiled covered container, and let sit, loosely covered, at room temperature for 2 hours. If your rising place is particularly warm, cut this down to 1 1/2 hours. After it has risen, gently take the container and place it in the refrigerator. Chill at least overnight, and up to about a week.
When you're ready to bake, gently take the dough out of the refrigerator. Tip it out onto a piece of parchment paper, taking care to not deflate any of the air that it has captured. Using a wet hand, shape the dough into a round, and smooth out the surface as best you can (keep wetting your hand to prevent the dough from sticking, and to wet the surface of the dough enough to smooth it out). Cover loosely with a piece of plastic, and allow to rise an hour and a half (less time if your rising area is warm).
Half an hour before the rising time is done, preheat your oven to 500 degrees. Place a large Dutch oven and its cover (making sure the cover doesn't have a meltable plastic knob) in the oven to preheat. While this is preheating, mix together the seeds for the topping.
When the dough has warmed and risen slightly, brush the surface completely with the egg wash (use a pastry brush if you have it, otherwise just wad up the plastic you'd used to cover the dough, and use it to gently blot the surface of the dough with the egg wash). Sprinkle the seeds for the topping evenly over the surface. Take a sharp serrated knife, and gently cut slashes 1/4" deep over the surface of the dough.
Carefully remove the preheated Dutch oven from the oven. Gently pick up the piece of parchment paper around the loaf, and gently lower it into the preheated pot. Cover, and gently place in the oven. Let bake 25 minutes, then remove the lid, and lower the oven temperature to 450 degrees. Let bake an additional 20-25 minutes, until the surface of the dough is browned (it may be difficult to see under the seeds), and the dough seems done to your liking. Lift it out of the pan, and cool on a rack. When nearly completely cool, slice and serve.