Preheat oven to 375F and grease an 8x8 casserole dish. If using a different size, adjust cook time.
In a large bowl, mix together the rolled oats, baking powder, cinnamon, nutmeg, and salt.
In a medium bowl, stir together the almond milk, eggs, maple syrup, and vanilla.
Add the wet mixture to dry mixture and stir until combined.
Add in the apples and pecans.
Pour mixture into baking dish and press down to make sure oats are soaked. Sprinkle on a few extra pecans and apple pieces, if desired.
Bake, uncovered, for around 40-45 minutes, until lightly golden brown.
Let cool for 5 minutes and then serve.
Store in refrigerator.