Preheat your oven to 350°F.

In the base of a stand mixer, cream together the softened butter and sugar until the mixture is pale and fluffy. Add the flour, cornstarch, and salt, and pulse until just combined.

Press the shortbread dough into a parchment-lined 9×13 inch pan, forming an even layer.

Bake for about 45 minutes until the crust is golden brown. Set aside to cool slightly.

In the bowl of a stand mixer or with a hand mixer, beat together the butter and brown sugar.

Once well combined, add the egg and mix until fully incorporated.

Add the vanilla, corn syrup, salt, bourbon, and orange zest. Mix well and set aside.

Spread the whole and chopped pecans evenly over the shortbread crust.

Pour the filling over the nuts, spreading it evenly.

Bake at 350°F for 30 minutes, until the filling no longer jiggles when shaken.

Allow the bars to cool completely.

Once cooled, drizzle with melted dark chocolate and sprinkle with sea salt, if desired.