Combine the pitted dates, water, and maple syrup in a small saucepan over medium heat. Bring to a boil and cook for 12 minutes, or until most of the liquid is absorbed, stirring frequently. Cool completely.
Preheat oven to 400 degrees F. Grease a 9x13-inch baking pan; set aside.
In a small bowl, stir together the all-purpose flour, old-fashioned rolled oats, baking soda and salt.
With an electric mixer, beat the unsalted butter and granulated sugar on medium speed until light and fluffy, about 3 minutes. Reduce the mixer speed to low and add the dry ingredients, beat only until all dry ingredients have been moistened.
Measure out 2 cups of the crust mixture and press evenly into the bottom of the prepared baking dish. Spread the date mixture evenly over top, then sprinkle with the remaining crust mixture.
Bake for 20 minutes, or until golden brown. Cool completely before serving.
