Preheat your oven to 375°F (190°C).

In a large bowl, combine the whole wheat pastry flour, old-fashioned oats, and salt. Mix well to ensure even distribution.

Add the coconut oil or cold butter into the dry ingredients. Use a fork or pastry cutter to blend until the mixture resembles coarse crumbs.

Stir in the maple syrup or honey until fully incorporated. Gradually add ice water, one tablespoon at a time, mixing until the dough holds together without being sticky.

Shape the dough into a disc, wrap it in plastic, and refrigerate for at least 30 minutes.

While the dough is chilling, prepare the apple filling. In another bowl, combine the sliced apples, lemon juice, maple syrup, cinnamon, nutmeg, and whole wheat flour or cornstarch. Toss gently to coat the apples evenly.

Roll out the chilled dough on a lightly floured surface to fit your pie dish. Place the rolled dough into the dish, pressing it gently against the sides.

Pour the apple filling into the crust, spreading it evenly. Dot with butter if desired for added richness.

Roll out the remaining dough to create a lattice top or a full crust, depending on your preference. If using a full crust, make sure to cut slits for steam to escape.

Brush the top crust with milk or an egg wash, then sprinkle with turbinado sugar if desired for a touch of sweetness and crunch.

Bake the pie in the preheated oven for 45-50 minutes, or until the apples are tender and the crust is golden brown.

Allow the pie to cool for at least 15 minutes before slicing. Serve warm or at room temperature.