Combine all dry ingredients in a bowl and mix well with a whisk. Set aside.
Combine all wet ingredients in a large mixing bowl and beat with a mixer until combined.
Add the dry ingredients to the wet and beat with mixer until well combined.
Scoop bread batter into a parchment lined bread loaf pan and smooth out with a spatula.
Sprinkle whole flax seeds and poppyseeds on the top of the bread batter, keeping the topping away from the edges.
Using a dampened spoon, gently press seeds into the bread batter so they stick.
Place loaf pan in a warm, draft-free area to rise until dough is no more than ½" above the edge of the pan, about 1 hour.
Preheat oven 350 deg F (180 C).
Drape foil loosely over bread and bake for 35 minutes.
Remove foil and bake another 20 minutes until the internal temperature of the bread is greater than 200 deg F (93 C).
Let bread rest in the pan about 5-10 minutes before lifting out from the pan.
Let cool completely before slicing.
1 ¾ cup + ¾ teaspoon tapioca starch
1 cup + 1 ½ tbs buckwheat flour
¾ cup + 2 tbs brown rice flour
Please note that gluten-free recipes work best with weight measurements because they are more precise than volume measurements. Gluten-free baking requires more precision and can be less forgiving than baking with regular all-purpose wheat flour.
These volume measurements were made from spooning each of the flours into the measuring cups/spoons (so they are not packed) and leveling them off.
The volume measurements are approximate. Make slight adjustments to the recipe as needed, adding a bit more water or a bit more tapioca starch or brown rice flour to achieve the correct dough consistency.
You cannot overwork gluten-free bread batter, so do not worry about over-mixing. You should mix the dry with the wet for about a minute to make sure it's well combined.
The bread will stay fresh in a bag on the counter for a day, or in the fridge for a few days. In this case, it is best to warm the bread in either the oven or microwave to make it soft again.
Slices of the buckwheat bread can be frozen if stored in a ziploc bag. Just put slices directly in the toaster!
This bread toasts up really nicely and makes really good avocado toast!