Add the chopped dates, granulated sugar, and water to a medium saucepan over medium-high heat. Bring to a boil. Remove from heat and set aside to cool.
In a large mixing bowl, combine the brown sugar, softened butter, oats, flour, baking soda, and salt (I usually use a pastry cutter).
Spread 1/2 of the crumble mixture evenly in a 10 x 15 pan (jelly roll pan) and press it into the pan. Gently spoon the date filling over the crust. Firmly press the remainder of the crumble mixture on top.
Bake at 350 degrees for 25 minutes. Let cool, then cut into 24 squares.