Whisk flour, baking soda and flour together. Whisk in salt. In a separate large bowl, cream sugar and butter together, using a handheld mixer or a stand mixer. Add in vanilla and eggs. Continue mixing until incorporated.
Slowly add in flour mixture into sugar mixture, in 3 or 4 increments. Mix until just combined. Add choclate and mix one final time.
Pour into a greased oven safe skillet. Bake for 25 minutes or until set.
Notes
For an extra touch, add a few pieces of chocolate chips to the very top of the skillet before you put it in the oven