Combine and stir all ingredients. Spray a small microwave safe bowl with cooking spray and pour in mixture. Cook in microwave for 1 minute and 30 seconds.
Lots of healthy and tasty ingredients can be added to this recipe. An egg substitute or a few egg whites can probably replace the egg nicely for less calories, fat, and cholesterol. I usually add a few packets of sugar substitute and 1/2 cup of blueberries or strawberries into the mixture. Sometimes, I skip adding the sugar substitute when microwaving and just sprinkle one packet on top when it is done for a little flair. Some banana and nuts would probably be delicious with this, too, either baked in or on top. The muffin is great for a quick snack, light breakfast, or sweet-tooth satisfyer. When cooked with the berries, it's about 3 inches in diameter. Any extras added to the basic recipe will, of course, change the nutritional information.
I found ground flaxseed in the baking aisle of my grocery store. After opening, you have to store it in the refrigerator. So far, I've added a teaspoon to my yogurt and a tablespoon to my oatmeal. Both tasted pretty good with the addition. The flaxseed has a lightly nutty flavor. Sparkpeople says "Nutrient and drug interactions may occur if consumption reaches or exceeds 1/4 cup daily," so do your research and talk with your doctor or pharmacist before using flaxseed.