Preheat the oven to 325°F (163°C) and grease a 10-inch cast iron skillet.
In a large bowl, prepare the brownie batter by whisking together melted butter, oil, sugars, eggs, vanilla, cocoa powder, cornstarch, salt, and flour. Then, fold in the chocolate chips.
Spread the prepared batter evenly into the greased skillet.
Sprinkle more chopped chocolate or chocolate chips over the top of the batter.
Bake for 22-28 minutes until a toothpick inserted near the center comes out with a few moist crumbs. Let it cool for about 45 minutes to set before serving.
Serve the warm fudgy brownie skillet, optionally with a scoop of ice cream on top.
This recipe was organized by Hemogry AI based on the video.
Nutrition data is estimated based on the video and may not be fully accurate.