Spray a medium to large microwave-safe mug (or small bowl) with cooking spray and inside combine all ingredients except raspberries. Gradually stir in raspberries.
Microwave on high for 2-3 minutes. (I checked my mug at 2 minutes and then let it cook 1 minute more.)
Stir in extra milk, yogurt or nut butter; if desired. Enjoy!
Notes
*Use certified gluten-free oats as needed. Quick cooking oats work too, if that's what you have on-hand. **Use any milk product that you prefer. ***I have not tried using frozen blueberries, but I'm sure it would work just fine. You could also try using another type of berry. - I adapted this recipe from my Blueberry Banana Microwave Baked Oatmeal recipe. Be sure to give that one a try too!