Place the egg whites in a small mixing bowl and let stand at room temperature for 30 minutes. Meanwhile, draw a 10 inch circle on a piece of wax paper and place (writing-side down) on a baking sheet. Variation: Draw 10 four inch circles on the wax paper.
Add vanilla and cream of tartar to egg whites. Beat with an electric mixer until soft peaks form. Add sugar, 1 tablespoon at a time, beating on high speed until very stiff peaks form and sugar is almost dissolved (about 5 minutes).
Using the back of a spoon, spread meringue onto the circle, building the sides up to form a bowl.
Bake in a 300oF oven for 35 minutes. Turn off the oven and let shell dry in the oven, with the door closed for one hour. Remove the shell from baking sheet and pull off wax paper. Store in an airtight container. Will keep indefinitely.
The traditional filling is simply fresh fruit of your choice and whipped cream and topped with fruit sauce. Another good one is ice cream, nuts, fruit and sauce ("banana split").