Preheat oven to 350°F. Line a 9x9-inch baking pan with parchment paper. Set aside.
In a large bowl, using a hand mixer, cream the butter and sugars together.
1 cup unsalted butter, ¼ cup granulated sugar, ½ cup brown sugar
Add in the salt and vanilla extract and beat until incorporated.
½ teaspoon kosher salt, 1 teaspoon vanilla extract
Add in the flour, little by little, beating after each addition. Mix until the dough comes together, being careful not to overmix.
2 cups all-purpose flour
Press the dough into the bottom of the pan.
Bake for 12-15 minutes until golden brown. Let cool.
While the crust is cooling, add the sweetened condensed milk, unsalted butter, brown sugar, corn syrup, vanilla extract, and salt to a saucepan. Stir over medium-high heat. Once the mixture begins to bubble, reduce the heat to a simmer. Continue stirring for 5-10 minutes until the mixture has thickened.
14 ounces sweetened condensed milk, ¾ cup unsalted butter, ¾ cup brown sugar, ¼ cup corn syrup, ½ teaspoon pure vanilla extract, ½ teaspoon kosher salt
Pour the caramel over the cooled shortbread layer.
Refrigerate for at least 1 hour to let the caramel set.
Place the chocolate chips and coconut oil in microwave safe bowl. Microwave the chocolate in 30 second increments. Stir until melted and smooth. Allow chocolate to cool for a few minutes.
3 cups chocolate chips, 3 tablespoons coconut oil
Pour the chocolate over the caramel layer and spread it out in an even layer. Return the bars to the refrigerator or freezer until the chocolate hardens.