Begin by preheating the oven to 350°F and prepare an 8-inch square baking pan with parchment paper, lightly greased with butter for easier removal.

In a mixing bowl, combine the softened butter with golden caster sugar and cream them until the mixture is smooth.

Incorporate the plain flour and vanilla extract into the creamed mixture, stirring until everything is well mixed.

Spread the mixture evenly in the prepared baking pan and press it down firmly with your fingers to create a compact base.

Bake the base in the oven for 20-25 minutes, or until it acquires a light golden shade.

While the base is baking, prepare the topping by gently melting the maple syrup, light brown sugar, and butter together in a saucepan over low heat.

Once melted, increase the heat to bring the mixture to a gentle boil; let it simmer for about 3 minutes while stirring constantly.

In another bowl, whisk the eggs, vanilla, and milk together, then slowly mix this into the warm syrup mixture, ensuring it's well combined.

Gently fold in the chopped pecans until they are evenly distributed throughout the mixture.

Pour the pecan topping over the baked shortbread crust and return the pan to the oven for an additional 30 minutes.

Once baked, let it cool completely before removing from the pan; for easier slicing, place it in the refrigerator for a while.

Store these delicious bars in an airtight container in a cool place and consume within 3 days for optimum taste.