Preheat the oven to 425F. and butter generously 2 large baking sheets.
In a small bowl cream together with a wooden spoon butter, sugar, vanilla, cinnamon, and salt. Add egg white and whisk until smooth. Stir in flour and stir in oats thoroughly. Drop batter by rounded teaspoons 4 inches apart onto prepared baking sheets. With the back of the spoon spread batter into 2 1/2-inch rounds and bake, 1 sheet at a time, in middle of oven 4 to 6 minutes, or until edges turn golden. Immediately transfer tuiles with a metal spatula to a rolling pin and cool in curved shapes. Tuiles may be made 1 day ahead and kept in an airtight container.
