1. To make the dumplings: In a large bowl, mix together the flours, ground flaxseeds, cream of tartar, baking soda, mint, ginger, and salt.
2. In a medium-size bowl, mix together the soy milk, corn oil, vegetable glycerin, and vanilla. Mix the wet ingredients into the dry ingredients. Stir in the brown rice and lecithin. Shape the dough into about 32 balls, 1 inch in diameter.
3. To make the sauce: Mix together all the sauce ingredients except the blackberries in a large saucepan and bring the pot to a boil over medium heat, stirring often.
4. Add the dumplings, reduce the heat to low, and simmer, covered, for 15 minutes. Add the blackberries and simmer, covered, for another 5 minutes.