Preheat your oven to 350°F (175°C) and line an 8x8-inch square baking dish with parchment paper, leaving an overhang for easy removal.

In a medium saucepan, combine the chopped dates and water. Bring the mixture to a gentle boil over medium heat, stirring occasionally.

Reduce the heat to low and simmer for 5 to 8 minutes, mashing the dates with a wooden spoon until they break down into a thick, jam-like consistency.

Remove the date mixture from the heat, stir in the vanilla extract, and set it aside to cool slightly.

In a large mixing bowl, whisk together the rolled oats, all-purpose flour, brown sugar, baking soda, and salt.

Pour the melted butter over the dry ingredients and stir with a fork or spatula until the mixture is completely crumbly and evenly moistened.

Press exactly half of the oat mixture firmly into the bottom of the prepared baking dish to create a solid, even crust.

Spread the cooled date jam evenly over the crust, then sprinkle the remaining oat mixture on top, pressing down very lightly.

Bake for 35 minutes, or until the oat topping is deeply golden brown and crisp to the touch.

Allow the squares to cool completely in the pan on a wire rack before lifting them out by the parchment paper and slicing into 8 neat rectangles.