Start by pre-heating your oven to 180c/350f.
In a pot, add the butter and place this over medium heat. Keep heating this, whiles stirring, until the butter turns a light brown colour.
Take this off the heat and pour the browned butter into a large bowl. Add both sugars and vanilla into this, mix this. Now mix in the eggs.
In a separate bowl, mix together the flour, salt, baking powder and baking soda. Add this into the other bowl and mix everything together, just until you can no longer see any flour.
Mix in most of the chocolate too, i like to save some to put on top before baking.
Add this dough into your cast iron skillet. Smooth it out, then sprinkle the saved chocolate on top.
Bake for around 35-40 minutes. The edges will be set, but the centre should still seem soft.
Once it has baked, let it cool down for about 10 minutes. Then add some ice cream on top and serve!!
