Add rolled oats and walnuts to food processor, high speed blender or coffee grinder and blend into a fine flour. Add to medium mixing bowl.
1 cup rolled oats, 1/3 cup walnuts
Add whole wheat flour and salt to oat/walnut mixture and stir to combine. Add maple syrup and 4 Tbsp water and thoroughly combine using a large wooden spoon. Add additional water, 1 Tbsp at a time, and continue combining until a stiff dough forms. When you squeeze a handful of it, it should look smooth and completely hold together.
1 cup whole wheat flour, 1/4 tsp salt, 2 Tbsp pure maple syrup, 5-7 Tbsp water
When the dough is thoroughly moist and holds together when squeezed with your hand, form it into a ball.
Place the dough on a lightly floured surface (whole wheat flour). Use your palm to gently flatten the dough into a disc. If the dough is too sticky, sprinkle with whole wheat flour. With a rolling pin, use firm and steady pressure to roll the dough until it's 12- to 13-inches in diameter.
Transfer the dough onto a 9-inch glass pie pan. Without stretching the dough, use your fingers to gently press it into the bottom of the pie plate. Patch any holes or tears with excess dough from the edges.
Use a knife to trim away the excess, and crimp the edges. To do so, use your index finger to push down on the edge of the pastry and use the finger and thumb of your other hand to pinch the pastry either side. Repeat around the rim of the pie. Use a fork to poke vent holes in the bottom of the crust.
For pies with a no-bake filling, bake the pie crust in a preheated 350 degree F oven for 22-28 minutes or until crisp. Cool before filling.For pies that will be baked, simply add the filling and bake per filling instructions. Cover the edges of the crust with foil or a pie shield if it begins to look too dry or crisp.
Notes
If the dough sticks to the rolling pin or counter, sprinkle more whole wheat flour on the counter or rolling pin. Another option is to place a piece of parchment paper underneath the dough and on top.If you realize the dough is too crumbly once you start rolling it out, return it to the bowl and mix in 1 more tablespoon of water.