Prepare the Date Filling:

In a medium saucepan, combine chopped dates, water, lemon juice, and optional sugar.

Heat over medium, stirring occasionally, until the mixture comes to a simmer.

Let the dates soften for 8-10 minutes, then mash them into a smooth paste. Add more water if needed for the desired consistency.

Set the date filling aside to cool.

Make the Oatmeal Crust:

In a large mixing bowl, combine rolled oats, all-purpose flour, brown sugar, baking soda, and salt. Whisk to combine.

Add the softened butter in small pieces and mix with a pastry cutter or fork until the mixture resembles coarse crumbs.

Stir in vanilla extract.

Set aside 1 1/2 cups of the oat mixture for topping.

Press the remaining oat mixture into the bottom of a greased 9×9-inch (23×23 cm) baking pan.

Layer the Date Filling:

Spread the cooled date filling evenly over the prepared oat crust.

Add the Topping:

Sprinkle the reserved oat mixture over the date filling, covering it evenly with a crumbly topping.

Bake to Perfection:

Preheat the oven to 350°F (175°C).

Bake the date squares for 25-30 minutes or until the top is golden brown and the filling is bubbly.

Let the squares cool completely in the pan before cutting them into squares.