RED-NOSED CAKES are what Karen quickly cooked up for the youngsters at her child's school. Our son needed reindeer treats for his class but forgot to tell me abut it until the day before, recalls Karen. It's the sort of situation that every mother finds herself in at one time or another! With no ready-made decorations on hand, Karen had to improvise. We stuck animal crackers in the cupcakes for antlers and used other sweets for the eyes and noses, she tells. All the students loved them. Her fast creations are helpful when you have lots of other preparations for a party. And they're easy enough for children to help with, too, notes Karen.