Preheat oven to 350 degrees.
Line a 9x9 inch or 9x13 square pan with foil , then lightly spray with a non-stick spray and set aside.
Over low heat or use microwaving, melt the butter, then add the sugar. Once the sugar has been blended in, add the milk chocolate chips, stirring until melted and smooth.
Remove from oven/stove and let cool down a few minutes before adding the eggs, one at a time mixing them in, then add in the coffee or vanilla extract.
Using a sifter or sieve, sift the cocoa powder and cornstarch into the saucepan, then add the salt. Using a mixer or whisk the batter vigorously until it's looks shiny and smooth.
Pour the batter into the prepared baking pan and bake for 22-28 minutes for a 9x13 pan or 32-38 minutes for a 9x9 pan until the brownies are set. You can jiggle the brownies to check for doneness for the top of the brownies. Do not over-bake or the brownies will become crumbly and dry.
Remove from oven and let cool in the pan for 45 minutes before removing and slicing. It's important to do this so they set up.
Store in sealed baggie or container or can be refrigerated sealed.