Preheat your oven to 350°F (175°C). Line a 9x13-inch metal or ceramic baking pan with parchment paper, leaving an overhang on the sides for easy lifting later.

Prepare the Shortbread Crust: In a medium mixing bowl, whisk together the flour, sugar, and fine sea salt. Pour in the melted butter and vanilla extract. Stir with a spatula until a soft, crumbly dough forms with no dry flour remaining.

Press the dough firmly and evenly into the bottom of the prepared 9x13 pan using the flat bottom of a measuring cup. Bake at 350°F for 18 to 20 minutes until the edges are lightly golden brown. Remove from the oven and set aside while making the filling.

Make the Brown Sugar Pecan Filling: In a medium saucepan, combine the melted butter, dark brown sugar, pure maple syrup, and heavy cream over medium heat. Whisk gently and bring to a gentle simmer for 2 to 3 minutes until the brown sugar is completely dissolved into a glossy amber syrup. Remove from heat and let cool for 5 minutes.

Gradually whisk the beaten eggs, vanilla extract, and sea salt into the warm caramel mixture in a steady stream until smooth and fully emulsified. Stir in the toasted pecan halves until evenly coated in luscious syrup.

Pour the gooey pecan caramel filling evenly over the warm pre-baked shortbread crust, using a spatula to spread the pecans all the way to the edges.

Return to the oven and bake at 350°F (175°C) for 22 to 25 minutes, until the center is set with only a very slight gentle wobble and the pecans are fragrant and caramelized.

Sprinkle flaky sea salt over the warm surface immediately upon removing from the oven. Let the bars cool completely in the pan at room temperature for at least 2 hours (or chill in the refrigerator for 1 hour) before lifting with parchment wings and slicing into neat squares with a sharp chef’s knife.