Step 1:
Grab your favorite microwave-safe mug. This recipe doesn’t rise too much, but make sure your mug can hold at least 8 ounces so there’s room to stir and cook safely.

Step 2:
Add 1 tablespoon of unsalted butter to the mug. Microwave it for about 15–20 seconds, just until it’s fully melted. You don’t want it boiling hot, just enough to melt smoothly.

Step 3:
Stir in 1 tablespoon of brown sugar and 1 tablespoon of granulated sugar. Mix well with a fork or small whisk until the sugars are dissolved into the butter.

Step 4:
Add 1/4 teaspoon of vanilla extract and 2 tablespoons of milk. Stir again until the mixture is smooth and well combined.

Step 5:
Now add 3 tablespoons of all-purpose flour and a small pinch of salt. Stir until a soft dough forms. The mixture should be thick but still moist—kind of like traditional cookie dough.

Step 6:
Fold in 2 tablespoons of semisweet chocolate chips. Distribute them evenly so every bite will have a little chocolatey goodness.

Step 7:
Gently smooth the top of the dough with the back of your spoon or fork so it’s flat. You don’t need to pack it down too firmly.

Step 8:
Microwave your cookie on high for 45–60 seconds, depending on your microwave’s power. Start with 45 seconds and check the texture. It should look set on top but still soft in the center. Avoid overcooking or it’ll turn rubbery.

Step 9:
Let your cookie cool for a minute or two. It will continue cooking slightly from residual heat and firm up just a bit more.

Step 10:
Dig in while warm! You can enjoy it straight from the mug or top it off with a scoop of ice cream, a drizzle of chocolate syrup, or a dollop of whipped cream for an extra treat.