In a glass mixing bowl, melt the butter.
Mix the sugar into the melted butter.
Beat and mix in the egg.
Add the oats to the bowl and sprinkle the flour, baking powder, and salt over the top of the oats.
Stir well until all ingredients are combined.
Preheat your oven to 375 degrees Fahrenheit.
Line a cookie sheet with foil.
Place small teaspoons of dough on the foil, leaving plenty of room, it will spread!
Bake the cookies for about 8-10 minutes, just as they begin to brown evenly.
Carefully remove from the oven and transfer the foil from the cookie sheet, let the cookies cool on the foil.
Once the cookies have cooled, the foil will peel off easily.
Cookies can be stored in an airtight container for 2-3 days.