Combine all ingredients except sprinkles into a mug or small bowl, mixing with a small whisk until a smooth dough forms. Stir in half of the sprinkles.
Line a medium-sized microwave-safe plate with parchment paper. Scrape out dough into the middle of the parchment paper. Shape dough to resemble a cookie shape (like a thick round disc).
Add remaining sprinkles to surface of the cookie. Microwave for approximately 50 seconds. You cookie might be done slightly sooner, but I don't recommend more than 50 seconds as it will turn the cookie hard and brittle. Cookie is best consumed right away.
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.