In a small mixing bowl, stir together flour, sugar, cocoa powder, and salt.
Add milk, butter, and vanilla. Stir well to incorporate.
Stir in 1/4 cup of the mini chocolate chips. Then divide batter between 2 microwave-safe cups (my cup holds 6 fluid ounces). Sprinkle the top of each cup of batter with an additional 1 teaspoon of mini chocolate chips.
Microwave both cups at the same time on high power for 2 minutes. Microwave strength varies, so adjust accordingly. The cakes should be cooked, but very moist, and a bit gooey in the middle. If you like your cake extra soft and gooey, cook for a bit less time. Allow cakes to cool for about 10 minutes prior to eating.
These are best when eaten within an hour or two of making them. As they cool, the chocolate chips will harden, so the cakes will be less gooey. But they're still very good. ;)
Nutrition information is automatically calculated by Spoonacular. I am not a nutritionist and cannot guarantee accuracy. If your health depends on nutrition information, please calculate again with your own favorite calculator.