1 1/2 cups (7 ounces) high-protein whole wheat flour
1 1/2 cups (8 ounces) brown rice flour
1/2 cup (2 ounces) ground flax seeds
3 large eggs
1/2 cup sunflower or canola oil
1/4 cup water
4 drops food-grade eucalyptus oil, optional (See Recipe Note)
7 sprigs parsley leaves, chopped fine (1/2 ounce)
Preheat the oven to 350ºF and line two cookie sheets with parchment paper.
In a medium mixing bowl, whisk together the whole wheat flour, brown rice flour, and ground flax seeds. In another large mixing bowl or the bowl of a stand mixer, whisk together the eggs, canola oil, water, eucalyptus oil, and parsley.
If you are mixing by hand, switch to a dough whisk or wooden spoon; if you are using a stand mixer, switch from a whisk to a dough hook. Stir the flour into the wet ingredients, one third at a time, until fully incorporated. When finished, the dough will come together into a ball and pull away from the sides of the bowl.
On a lightly floured work surface, use a rolling pin to roll the dough out to 1/4-inch thickness. Use a cookie cutter to cut the dough into desired shapes, then gently transfer to the lined baking sheets with a thin spatula. The biscuits will not spread out much during baking — you can lay them down about 1/3-inch apart.
Gather together the leftover dough, knead it back into a ball, then roll it out again to cut out more cookies — it will continue to remain malleable with repeated rollings due to its fairly low gluten content. Continue to do this until you’ve used up the dough and filled two cookie sheets with biscuits.
Bake the treats for 20 minutes. Remove from oven, and while still warm, transfer the treats to wire cooling racks.
Return the racks of cookies to the oven and turn the heat down to its lowest setting (if your oven has a "keep warm" function, use this; otherwise, 180-200ºF is ideal). After one hour, turn the oven off and leave the cookies in the oven for another hour or so, or overnight.
Let the treats cool to room temperature, then store in a cookie jar or other lidded container for up to two months, or freeze for up to three months.