Preheat oven to 325 degrees. Coat an 8 inch baking dish with non-stick cooking spray. In a large bowl, mix 2 cups old-fashioned rolled oats, 3/4 dried cranberries (or raisins), 1 teaspoon baking powder, 1/4 teaspoon salt, and 1 teaspoon cinnamon.
In another bowl, whisk 2 eggs, 1/4 cup maple syrup, 2 cups milk, 1 teaspoon vanilla, extract, and 4 tablespoons melted unsalted butter. Add this mixture to the oat mixture and stir to combine. Stir in 1 finely chopped apple.
Pour into baking dish. Sprinkle dried cranberries and slivered almonds on top. Bake about 45 minutes, until top is golden and set. Let cool slightly and cut into squares.