¾ cup flour (measure the flour by spooning it into a measuring cup, the leveling off with the flat
end of a knife)
½ cup (1 stick butter), plus more for skillet
1¾ cups semisweet chocolate chips, divided
1 cup sugar
3 large eggs, lightly beaten
1 teaspoon pure vanilla extract
Heat the oven to 325 degrees. Grease a 10-inch cast-iron skillet with butter; set aside. Toss ¾ cup chocolate chips with 1 teaspoon of the flour, set aside. In a microwave-safe bowl, microwave butter with 1 cup chocolate chips on HIGH for 1 minute, stirring at 30-second intervals. Whisk in the sugars and salt, blending well. Add eggs and vanilla to sugar mixture, whisking until mixture no longer appears grainy. Stir in the remaining flour, blending until just combined.
Fold in the reserved chocolate chips. Pour batter into skillet and bake for 30 minutes, or until a toothpick inserted in center comes out with a few moist crumbs. (Do not overbake. The skillet will be very hot and brownies will cook a little more after the skillet is removed from the oven.) Brownies may be served directly from the skillet, like a cobbler, and served with ice cream. Or, allow the brownies to cool on a wire rack and cut into wedges, or into desired shapes with a cookie cutter.