• Melt the butter in a saucepan over medium heat. Use a light colored pan if possible as this will help you better notice the butter change color. Stir the butter constantly. It will start to foam and will change to a light, amber color then to golden brown in about 5-7 minutes. Once the butter is golden brown, remove from heat and pour into a heat safe bowl. Allow to cool for at least 15 minutes.
• Preheat oven to 325 F. Line a 13 x 9 inch rectangular pan with parchment paper. Leave some excess parchment paper on two sides. This will make the cookie easy to remove once baked.
• In a medium sized bowl, whisk to combine the flour, baking soda and salt. Set aside.
• In a large bowl, stir together the the brown butter and brown sugar with a wooden spoon or spatula until combined. Scrape down the sides of the bowl then mix in the vanilla and the egg yolks.
• Stir in the dry ingredients until just combined, being careful not to overmix. Stir in 1 cup of the toffee bits then press the cookie dough evenly into the pan.
• Cook for 19–21 minutes or until the sides are golden brown but the center is still soft. Set the pan on a cooling rack to cool for at least 30 minutes.
• While the cookie is cooling, make the chocolate caramel sauce.

FOR THE CHOCOLATE CARAMEL SAUCE

• In a saucepan with tall sides, stir to combine the sugar, water, and corn syrup. Bring to a boil over medium heat and allow to cook/bubble without stirring. Gently lift and swirl the pan a few times to help the ingredients cook evenly. Cook until caramel turns light to medium amber (about 8 to 10 minutes) then remove from heat.
• Immediately but carefully add the heavy cream followed by the butter, salt and vanilla and finally the chocolate. The mixture will bubble and hiss with the addition of these ingredients. Stir with a whisk, spatula or wooden spoon until smooth.
• Drizzle about 1/4 - 1/3 cup of the chocolate caramel sauce over the cooled cookie (refrigerate the remainder of the caramel for future use).  Top with the remaining toffee bits, chopped chocolate and chopped almonds. Top with flaky sea salt if desired.  Pull up on parchment paper to remove from pan. Set bars on a cutting board and use a sharp knife to cut them. Store leftovers at in an airtight container at room temperature for up to 3 days.