Preheat your oven to 375°F (190°C). Lightly grease an 8x8-inch or 9x9-inch ceramic baking dish with butter or cooking spray. In a large bowl, whisk together the rolled oats, baking powder, ground cinnamon, nutmeg, ground ginger, fine sea salt, and 1/4 cup of the chopped pecans until evenly combined.

In a separate medium bowl, whisk together the oat milk, pure maple syrup, eggs, melted butter, and vanilla extract until smooth, pale, and slightly frothy.

Scatter the diced Honeycrisp apples evenly across the bottom of the prepared baking dish. Spread the dry oat mixture evenly over the apples.

Slowly pour the milk custard evenly over the entire dish, ensuring all dry oats are submerged and moistened. Tap the dish gently on the counter to eliminate air pockets.

Scatter the remaining 1/4 cup of chopped pecans and 1 tablespoon of turbinado sugar evenly across the top for a crackly caramelized crunch.

Bake uncovered for 35 to 40 minutes, until the center is set, the edges are bubbly golden-brown, and a toothpick inserted into the center comes out clean.

Let rest for 5 to 10 minutes before slicing into generous squares. Serve warm with an extra drizzle of pure maple syrup and a splash of cold cream or oat milk.