01 - Preheat oven to 350°F. Grease a 9x9-inch baking dish using butter or nonstick spray.
02 - In a large mixing bowl, blend old-fashioned rolled oats, light brown sugar, ground cinnamon, baking powder, and salt until thoroughly combined.
03 - In a separate bowl, whisk eggs, whole milk, maple syrup, melted unsalted butter, and pure vanilla extract together until smooth.
04 - Pour the wet mixture over the dry ingredients and stir gently just until fully moistened. Fold in chopped nuts and dried fruit if using.
05 - Spread the prepared batter evenly into the greased baking dish and smooth the surface.
06 - Bake in preheated oven for 30–35 minutes, until the center is set and the top appears golden brown.
07 - Allow the bake to cool for 5 minutes before slicing. Serve warm with extra maple syrup drizzled over each portion if desired.