I wanted a really buttery thumbprint cookie, but with the egg yolk which I felt would be important to bind the cookie. I tripled the recipe and used jam in the center and drizzled with cream cheese frosting I warmed in the microwave. These cookies came out perfectly. I really liked this recipe and I read ALL the other thumbprint recipes and this was in my opinion the Best!!!
I filled mine with seedless raspberry preserves mixed a little bit of chambord (Raspberry liquer). There were gone in a New York Minute! I suggest if you are taking these anywhere...make a triple batch! You can't eat just one!