In a small saucepan, place the water and diced potatoes, and bring to a boil. Reduce heat to low and simmer for 15 minutes or until the potatoes are tender. Drain well, reserving the cooking liquid for another use, and set cooked potatoes aside to cool. Transfer the cooled potatoes to a food processor and process until smooth. Add the warmed soy milk, 1 T. maple syrup, and yeast, and process for 30 seconds to combine. Allow the mixture to sit for 10 minutes.
Add both types of flour and salt, and process for 30-60 seconds or until the dough comes together to form a ball. Drizzle a little safflower oil into a large bowl, place the ball of dough in the bowl, roll the ball of dough around in the bowl to evenly coat it on all sides with the oil, and cover with a towel. Place the bowl in a warm place and allow the dough to rise until doubled in bulk, about 1 hour. Lightly oil (or spray with a light mist of oil) a large cookie sheet and set aside.
When the dough has doubled, punch it down, and transfer to a floured work surface. Roll the dough into a 16-inch circle. Fold it into quarters, carefully transfer it to the prepared cookie sheet, and then unfold the dough to reform it into a 16-inch circle. Measure out 2 T. of the apple juice concentrate and set aside. In a large bowl, place the remaining apple juice concentrate, along with the remaining ingredients, and toss gently to combine. Place the filling in the center of the pastry circle. Fold up the edges of the pastry slightly, creating pleats here and there to keep the circular shape intact, and create a 3-4-inch wide border of pastry around the filling.
Bake at 350 degrees for 25 minutes. Remove the cookie sheet from the oven. Brush the edges of the pastry with the reserved 2 T. apple juice concentrate. Return the cookie sheet to the oven, and bake the galette an additional 5-7 minutes or until golden brown. Allow the galette to sit for 10 minutes. Transfer to a large platter for service. Sprinkle a light dusting of Veganized Powdered Sugar over the top of the galette and cut it into 8 pieces.
Serves 8
