01 - Preheat oven to 350°F (175°C) and grease a 9x9-inch baking dish with butter or nonstick spray.
02 - In a large mixing bowl, thoroughly mix rolled oats, chopped nuts, baking powder, ground cinnamon, ground nutmeg, and salt.
03 - In a separate bowl, whisk together milk, eggs, melted butter, maple syrup, and vanilla extract until smooth.
04 - Pour wet mixture over the dry ingredients and stir until fully combined. Gently fold in diced apples and dried fruit.
05 - Evenly spread the oat mixture into the prepared baking dish, smoothing the top with a spatula.
06 - Place in the oven and bake for 35 minutes, or until the top is golden and the center is set.
07 - Allow to cool for 5 minutes before portioning. Serve warm, optionally with additional milk or yogurt.