Mix together oatmeal, brown sugar, and flour. Stir in melted butter.
Add the egg and vanilla, and blend well.
Place ½ teaspoons of batter on sheet pan at least 2 inches apart. Bake until lightly browned, about 7 minutes.
When slightly cooled, remove from sheet pan.
To make Lace Cups, place 1 Tbsp dough on cookie sheet, 4 per sheet. Bake for 6 minutes. When still pliable and fairly warm, remove from sheet pan and place each one over an overturned juice glass and mold with hands. No need to spray glass with Pam. Remove when cooled. Makes about 12-14 cups.