Step 1

Preheat the oven to 325 F. Place cast iron skillet on stovetop burner.

Step 2

Cut butter into 6 chunks and place in skillet with the chocolate. Cook over very low heat, stirring occasionally with a wooden spoon.TIP - Because the heat is low, it can take some time, so measure out your other ingredients while it's melting, so you aren't tempted to turn up the heat!

Step 3

When the chocolate and butter are completely melted, remove pan from the heat and add both sugars. Stir until everything is combined.

Step 4

Add eggs, one at a time, stirring well after each addition.

Step 5

Add vanilla and stir well.

Step 6

Add flour and salt and stir until there are no traces of flour left.

Step 7

Use a rubber spatula around the edge of the pan to clean off the sides and get all the batter into the middle.

Step 8

Place skillet in the oven and bake for 50 minutes. Insert a toothpick into the center to test for doneness. The toothpick should come out clean, with the possibility of a couple of crumbs. If it's still wet, put it back in the oven and bake at 5-minute intervals.

Step 9

Allow to cool on a wire rack for about 15 minutes. If you like warm brownies with ice cream and chocolate sauce, cut a wedge now. Otherwise, cool the brownies completely before cutting them into wedges.