Recipe by Nicole Gaffney (ColeyCooks.com)
Preheat the oven to 350 degrees F.
Whisk together melted Finlandia butter, granulated sugar, brown sugar and salt in a medium bowl. Add the egg yolk and vanilla extract, then continue whisking until light and fluffy, about 2 minutes.
Add the flour and baking soda, then use a rubber spatula to mix until all the flour is incorporated. Add the chocolate chips and mix until just combined.
Spread the batter into a 5″, 6″, or 7″ cast iron skillet, cake pan, or baking dish, then sprinkle with sea salt if desired.
Bake for about 20 minutes, or until the edges are golden brown and set. The center will still be quite doughy. Bake for an additional 5-10 minutes if you prefer a more well-done cookie.
Allow the cookie to cool down for about 15 minutes. Top with a scoop (or two) of vanilla ice cream, salted caramel and/or hot fudge sauce, whipped cream, chocolate shavings and/or sprinkles and serve immediately.