Preheat the oven to 350 degrees. Lightly grease 2 8 inch cast iron skillets or 1 9 x 13 in baking pan.

In the bowl of an electric mixer, beat the butter and sugars on medium speed until light and fluffy, about three minutes. Add eggs, one at a time, beating well after each addition, and scraping down the bowl as needed. Beat in vanilla extract.

In a separate bowl, whisk together flour, soda, salt, and baking powder. With the mixer on low speed, slowly add flour mixture to the butter mixture and beat until just combined. Stir in oatmeal.

Press dough into 2 8 in cast iron skillets or a 9 x 13 inch pan. (You can also freeze half the dough to use later). Scatter heath bits and chocolate chips across the top. Bake in the preheated oven for 20-30 minutes or until outsides are set and center is still a bit gooey. Allow to set up before slicing and serving. Or don't...and just enjoy that warm, melty mess.