In a saucepan, bring water, sugar, salt, cinnamon and nutmeg to a boil.
Stir in oats.
Return to a boil; cook 1 minute.
Remove from the heat; cover and let stand for 5 minutes.
Pour into a greased 8-1/2-in.x 4-1/2-in.x 2-1/2-in.loaf pan.
Cover and refrigerate overnight.
Unmold and cut into 1/2-in.slices.
Fry in butter in a skillet over medium heat until browned, about 6-8 minutes