Heat a conventional oven to 200 degrees Celsius (392 degrees Fahrenheit).
Melt butter in a saucepan and add oatmeal. Remove the saucepan from the heat.
Whisk the remaining ingredients together and add the butter and oatmeal mixture.
Place 18 dollops of dough - arranged on two baking trays - 9 on each (no more).
Bake in the oven for 5-8 minutes until they get a little color on the edges - let the cookies cool on a wire rack until they are completely cold and crispy!