Salted Caramel Shortbread Bars

For the shortbread:
10 tbsp butter, softened
1/2 cup sugar
1/2 tsp salt
1 egg yolk, beaten
1 2/3 cup flour

For the caramel:
1 cup butter
1 cup brown sugar
3/4 cup corn syrup
2 tsp salt
4 tbsp sugar
4 tbsp cream
1 1/2 tsp vanilla
sea salt, for sprinkling

Preheat oven to 350, and line an 8x8-inch baking pan with parchment paper.
In a large bowl, combine the butter, sugar and salt.
Add in the egg yolk, and mash together with a fork.
Add in the flour, and use your fingers to combine together.
Press the dough down evenly into the prepared pan.
Refrigerate the dough for 30 minutes, and then bake at 350 for 20-25 minutes, or until golden brown.
Once the shortbread has cooled, start making the caramel. In a small saucepan, combine the butter, brown sugar, corn syrup, salt, sugar, and cream. 
Bring to a boil, and stir for 5-10 minutes, until the mixture is thick and bubbly. 
Remove heat, and stir in the vanilla. 
Pour the caramel over the shortbread, and refrigerate for 2 hours.
Remove the salted caramel shortbread from the pan, and sprinkle with the salt flakes.
Cut into bars, and then into triangles.