01 - Preheat oven to 350°F. Grease a 9x9-inch baking dish.
02 - In a large mixing bowl, blend rolled oats, chopped nuts, baking powder, cinnamon, nutmeg, and salt.
03 - In a separate bowl, whisk together milk, eggs, melted butter, maple syrup, and vanilla extract.
04 - Pour the wet ingredients into the bowl of dry ingredients. Stir gently until fully incorporated.
05 - Fold in diced apples and raisins or dried cranberries until evenly distributed.
06 - Evenly spread the oat mixture into the prepared baking dish. Bake for 35 minutes until set and golden.
07 - Allow to cool for 5 minutes before slicing. Serve warm, optionally with additional milk or a dollop of yogurt.