Prepare the Pastry Case: Preheat your oven to 160°C (325°F) / 140°C fan / gas mark 3.
Roll out your shortcrust pastry and use it to line a 20cm / 8-inch deep tart tin.
Line with baking parchment, fill with baking beans, and blind-bake for 15 minutes until the edges are golden.
Bake Again: Carefully remove the parchment and beans. Prick the base of the pastry with a fork and return it to the oven for another 12-15 minutes, until the entire case is a light golden brown.
Set aside on a wire rack to cool completely.
Make the Date Paste: While the pastry bakes, place the pitted dates, 150ml (5.1 fl oz) / ⅔ cup of water, and the bicarbonate of soda in a small saucepan.
Simmer over a medium heat for about 5 minutes until the dates are very soft and the water has mostly evaporated.
Don't worry if the dates turn a dark colour!
Create the Filling: Using a hand blender or food processor, blitz the date mixture into a smooth paste.
In a large bowl, combine this date paste with the beaten eggs, black treacle, golden syrup, double cream, fresh breadcrumbs, and the pinch of salt.
Mix until everything is well combined.
Assemble the Tart: Once your pastry case is completely cool, spread the lemon curd in an even layer across the base. Gently pour the treacle and date filling over the top.
Bake to Perfection: Place the tart in the preheated oven and bake for 45-50 minutes. The filling should be set and feel firm to the touch when done.
Cool and Serve: Let the tart cool completely in its tin on a wire rack.
Once cool, carefully trim any overhanging pastry from the edges. Just before serving, dust generously with icing sugar and offer with a dollop of extra double cream.
Don't skip the blind-baking step; it's crucial for preventing a soggy bottom and ensuring a crisp pastry crust.
