Step 1
Start by heating your oven to 400°F (200°C) and greasing a 10x14-inch baking dish with cooking spray. In a large bowl, beat together the brown sugar and butter until the mixture is smooth and creamy. In another bowl, whisk together the whole wheat flour, all-purpose flour, salt, cinnamon, baking soda, and allspice. Gradually add the dry ingredients to the butter mixture, stirring well to combine. Then fold in the oats using a wooden spoon until everything is mixed. Press half of this oat mixture firmly into the bottom of your prepared pan.



