Place sugar, flour, cocoa powder and salt in a mug (I use a 12-ounce mug). Use a small whisk or fork, and stir until combined, and free of lumps. Stir in chocolate chips. Add oil, milk, and vanilla, stir with a spoon or small rubber spatula until just combined (try not to over mix it). Sprinkle a few additional chocolate chips over the top.
Cook in the microwave for about 90 seconds (microwave times may vary). Eat immediately with ice cream, whipped cream, powdered sugar, or berries.
This brownie recipe makes 1 brownie that's big enough to serve two people...if you feel like sharing. I have even stretched it between my family of four when we eat it with vanilla ice cream.Microwave cook times will vary. Cook it for one minute, then an additional 15 seconds until done. Don't overcook it!!