1. Preheat oven to 375 degrees Fahrenheit. Grease large baking dish with butter or nonstick spray (I used a 10-inch oval dish, but a 9x9, 7x11, or really any large baking dish will be fine here.
2. Shred your apples, and set them aside while you make the oatmeal batter.
3. Put apple cider, maple syrup, almond butter, melted butter, egg, and vanilla in a mixing bowl and whisk to combine. Then, dump in all remaining ingredients, including the shredded apples and any liquid that may have pooled around them, and stir.
4. Pour the oatmeal mixture into the prepared pan, and set aside while you mix up the pecans.
5. In your now empty mixing bowl, quickly toss together the chopped pecans, maple syrup, cinnamon, and salt. Evenly distribute them over the top of the oatmeal. If desired, thinly slice an additional apple and arrange it on top of the oats. This really just makes them look extra pretty, but isn't necessary.
6. Bake for 35-45 minutes, depending on the size of your pan, or until the oatmeal is not longer wet/jiggly in the middle and the pecans are toasted.
7. Let oatmeal cool at room temperature for at least 5 minutes before slicing and serving. To store leftovers, let cool completely and transfer to an airtight container for up to 5 days in the fridge.