Preheat oven to 180℃ (160℃ fan forced). Grease an 8 cup capacity ovenproof dish with non-stick cooking spray. Whisk flour, brown sugar, ginger and cinnamon in a bowl, make a well in the centre. Add the melted butter, milk, vanilla extract and the drained dates, mix until combined. Transfer mixture to the prepared dish and smooth the surface. Set aside.