Preheat your oven to 350 degrees Fahrenheit. Line an 8x8-inch baking pan with parchment paper and spray with non-stick baking spray.
In a bowl, beat 1/2 cup of unsalted butter until light and fluffy. Add 1/2 teaspoon of vanilla extract, 1/4 cup of confectioners' sugar, and 1/4 teaspoon of salt. Mix until combined.
Gradually mix in 1 cup of all-purpose flour until just combined.
Dump the mixture into the prepared pan, spreading it into an even layer. Bake for 14 to 15 minutes, or until lightly browned. Allow to cool.
Combine 16 ounces of semi-sweet chocolate, 1 can of sweetened condensed milk, and 2.5 tablespoons of unsalted butter in a microwave-safe bowl. Microwave on low in 30-second increments until melted and smooth.
Stir in 1 teaspoon of pure vanilla extract. Spread this chocolate mixture over the cooled shortbread layer.
Drizzle 1/2 cup of salted caramel sauce on top and sprinkle with 1/2 cup of toasted pecans and 1 teaspoon of flaky sea salt.
Refrigerate for at least 2 hours until firm. Cut into squares and serve.
