Preheat your oven to 325ºF. This is crucial for ensuring your brownies bake evenly and achieve that perfect texture.
Grease a deep 10-inch skillet with non-stick cooking spray, ensuring it’s well coated to prevent sticking. This will help the brownies release easily after baking.
In a large, microwave-safe mixing bowl, gently melt the butter and semisweet chocolate together. Stop to stir occasionally until the mixture is smooth and glossy. The aroma will be incredible!
Once melted, whisk in the instant coffee and let the mixture cool slightly before moving on to the next step.
After cooling, whisk in the sugar until well combined, then add the eggs one by one, beating well after each addition. Finally, stir in the vanilla.
Add the salt followed by the flour, mixing until just combined. Be careful not to overmix; we want that chewy, fudgy texture!
If you’re using them, fold in the milk chocolate chips until evenly distributed throughout the batter.
Spread the batter evenly into the prepared skillet. The batter will be thick, so take your time to smooth it out.
Bake in the preheated oven for about 55 minutes to 1 hour and 10 minutes. Keep an eye on them as baking times can vary. You want the edges to look set, but the center should still be soft.
Once they’re done, let the brownies cool in the skillet on a wire rack before cutting them into wedges. If desired, serve warm with a scoop of ice cream!