Preheat oven to 350 degrees and prep an 8x8 baking dish by lightly greasing it and lining with parchment, allowing some over-hang to help lift the dessert from the pan after baking.
In a small pot, add water, dates, lemon and maple syrup. Bring to a boil and then turn down heat to allow contents to simmer (uncovered) for 5 minutes or until dates are soft.
Remove from heat and set aside to cool.
While dates cool, prep pastry. In a mixing bowl combine oats, flour, sugar, cinnamon and baking powder. Set aside.
Melt butter and coconut in a small bowl together, stirring well to combine. Add butter/oil mix into dry ingredients and use a spoon or spatula to combine. Press half the pastry mix into the prepared baking dish. Set the other half aside.
Transfer cooled date mix into a food processor, add baking soda and pinch of salt. Process on medium-low until paste forms.
Pour date paste over the first layer of pastry mix in the baking dish, spreading evenly.
Using your hands, gently crumble and pat down the remaining pasty mix over the date paste.
Bake for 40-45 minutes on middle rack, until top is golden brown. Transfer to cooling rack and leave in dish for 30 minutes before removing. After 30 minutes, carefully remove from dish using sides of parchment paper and allow to cool for 2 hours before serving or storing.
Store in airtight container for up to 3 days. Can also be refrigerated and frozen.