I’m always on the lookout for sites that teach me something new. This site has an excellent article on making sablé breton tartlets in small hemispherical molds. (I bought a set of hemispherical molds in various sizes last year, just so I had them for chocolate work and things like this.)
With the addition of 3/4 tsp baking powder and one tsp vanilla, this dough is exactly the same as the one I used for the gateau basque. Interesting technique, leveling the cookies with a microplane grater.