In a medium saucepan, combine the 1 cup of water and the 3 cups of pitted dates. Bring to a gentle simmer over medium heat, stirring occasionally, for about 5 to 7 minutes until dates have softened. Stir in 1 teaspoon of vanilla extract and set aside to cool.
In a large mixing bowl, combine the 2 cups of rolled oats, 1 cup of flour, 1 cup of brown sugar, 1 teaspoon of baking soda, 1/2 teaspoon of salt, and 1 teaspoon of cinnamon. Whisk until well blended.
Add the cooled date mixture to the bowl with the dry ingredients and mix thoroughly until well combined.
Add 1 cup of cold butter cubes to the mixture and work it in until it resembles coarse crumbs.
Preheat your oven to 350°F (175°C) and grease your 9x9 inch baking pan.
Press half of the oat mixture firmly into the bottom of the prepared pan.
Spread the date mixture evenly over the pressed oat base.
Crumble the remaining oat mixture over the top of the date filling.
Bake for 25-30 minutes or until the top is golden brown and the edges are bubbling.
Allow to cool completely in the pan before slicing into squares.