Preheat the oven to 350°F. In a mixing bowl, combine flour, butter, granulated sugar, salt, and vanilla extract until a dough forms. Press this mixture into an 8x8-inch baking dish lined with parchment paper. Bake for 20-25 minutes or until lightly golden. Allow to cool.

In a saucepan, melt butter and brown sugar over medium heat. Add sweetened condensed milk and corn syrup. Stir continuously until the mixture thickens and turns a caramel color. Remove from heat and stir in vanilla extract. Pour over the cooled shortbread layer and let it set for about 30 minutes.

In a microwave-safe bowl, combine chocolate chips and heavy cream. Heat in 30-second intervals, stirring between each, until a smooth ganache forms. Spread this over the caramel layer.

Optionally, sprinkle flaky sea salt over the chocolate layer for an added crunch and contrast. Chill in the refrigerator for at least 2 hours before serving. Slice into squares and enjoy!