- Heat your oven to 160°C/325°F. Line a square baking tin with tin foil and grease with butter.
- Sift your plain flour into a large mixing bowl and add your cold cubed butter. Rub in with your fingers until the mixture resembles breadcrumbs, then add your sugar and combine into a dough.
- Press your dough into your tin and prick with a fork. Bake for 20 mins, then leave to cool to room temperature.
- Heat your oven to 180°C/350°F.
- In a small saucepan over a medium heat, add your sugar, syrup, butter and double cream. Whisk until your butter is melted, then sprinkle over your cornflour and whisk until your mixture is silky and thick. Remove from the heat, then whisk through your egg yolks, vanilla and salt and stir to combine before adding your pecans. Leave to cool slightly.
- Pour your mixture over your shortbread, then bake for about 25 mins until the mixture is set.
- Heat your cream in a jug until steaming. Pour over your milk and dark chocolate in a bowl and leave to stand for a couple of minutes before stirring to combine. Pour this mixture over your shortbread, spread evenly over the surface and pop in the fridge until set, a couple of hours.
- Cut into squares and serve!