Preheat oven to 400 degrees F. Butter or grease the muffin tin. Do not use foil or paper liners - the muffins don't come out as good if you use liners.
Cook the old-fashioned oatmeal. Simply pour 1 cup of water into a pot and the dry oatmeal. Stir gently. Turn heat to medium-low and cook approximately five minutes, stirring frequently to prevent burning or sticking (some will stick anyway). When the oatmeal is cooked, you should have 1 cup cooked oatmeal, which you will use in the muffin batter. Turn off the stovetop and allow the oatmeal to cool while you mix the remaining ingredients.
In the large bowl, mix the dry ingredients by hand: flour, sugar, baking powder, salt. Set aside.
In the smaller bowl, beat the egg. Add milk. Add the cooked oatmeal and stir together
Melt butter or shortening.
Quickly stir the melted butter or shortening into the milk, egg, and oatmeal mixture. Stir by hand until everything is mixed together evenly.
Stir the wet mixture (butter, oatmeal, milk, egg) into the dry ingredients. Mix the batter by hand, stirring until everything is evenly mixed and no flour sticks to the bowl.
Spoon batter into muffin tins until it is just a little under the rim, about 2/3 full.
Bake for 20 minutes. Test to see if they are done by inserting a toothpick into the center of one muffin and pulling it out. If the batter doesn't stick to it, your muffins are done.
Place the pan on a wire rack to cool the muffins. Allow it to cool completely. Use a knife to gently separate the muffin from the tin. Finish cooling muffins on a plate or rack.
Store fresh muffins at room temperature on a plate. Cover the plate with plastic wrap.
Freeze muffins by placing completely cooled muffins into a freezer-safe, zip-lock bag. Label with name and date and place in freezer. They keep for up to 3-6 months. To defrost, leave it out overnight, or pop it in the microwave for 30 seconds.
