Cake flour and olive oil make these thumbprint cookies super-tender; the compelling hints of vanilla and orange come courtesy of our wonderful Fiori di Sicilia flavoring. A jewel of tart jam in the center completes this very pretty picture.
To make the dough: In a medium bowl, sift together the flour, confectioners’ sugar, and salt; set aside.
In a large bowl, beat together the butter and olive oil until smooth. Mix in the zest, vanilla, Fiori, and yolks.
Add the dry ingredients and mix just until combined; scrape the bowl and mix briefly once more to be sure no dry flour remains.
Shape the dough into a disk, then wrap and chill for at least one hour. The dough can be made up to three days in advance.
When you’re ready to bake, preheat the oven to 325°F. Line two baking sheets with parchment.
To shape the cookies: On a lightly floured surface, roll the dough 1/4” thick. Dip thumbprint cutters in flour and cut out shapes. Before moving the cutter, press the plunger down three or four times to fully imprint the pattern.
Use a spatula to transfer the cookies to the prepared baking sheets. Continue with the remaining dough, gathering any scraps and re-rolling as necessary.
If you don’t have thumbprint cutters, scoop the dough by the tablespoonful (a tablespoon cookie scoop works well here) onto the prepared baking sheets. Use your wet finger or thumb to press an indentation into the center of each cookie prior to baking.
To bake and finish the cookies: Bake the cookies for 12 to 15 minutes, until the edges just begin to brown. Remove them from the oven.
Leave the cookies on the baking sheets and fill the center of each with about a teaspoon of jam while still warm; this will help the jam melt slightly and give it a smooth finish.
Cool the cookies completely before removing from the pan.
Storage information: Store the cookies, well wrapped and any layers separated by parchment or wax paper, at room temperature for several days; freeze for longer storage.