Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, line a 8" square tin with greaseproof paper. I grease the tin first with a little butter to help the paper stick to it
To make the shortbread biscuit base mix the golden caster sugar and butter together into a bowl until creamy, using a spoon, or an electric mixer if you have one
Add the plain flour and vanilla, and mix in
Tip the mixture into the tin and press it down with your fingers until compact and even
Bake the shortbread biscuit base for 20-25 minutes, until lightly golden
For the topping, put the maple syrup, light brown sugar and butter into a pan and melt them together on a low heat
Bring the mixture to a boil and boil for 3 minutes - stirring constantly - then remove from the heat
In a bowl whisk the eggs, vanilla and milk together
Add the egg mixture to the maple syrup mixture very slowly, add a little bit and whisk as you add it
Then stir in the chopped pecans
Pour the topping over the cooked base and put it back in the over for 30 minutes
Let it cool fully before removing from the tin and cutting into squares, I also highly recommend chilling it in the fridge to make it easier to cut
Store in an airtight container in a cool place and eat within 3 days