Peel, core and slice apples. Sprinkle with cinnamon and place in bowl. Fill center hole with brown sugar, add a bit of butter on the top of each apple.
Cover bowl with plastic wrap, pierce to vent. Microwave for approx. 1 to 1 ½ minutes per apple. Check for done-ness (should be soft enough to cut easily, but not mushy). We usually run them for a minute per apple to start, then check them and run a bit longer as needed.