I made these shortbread hearts from leftover dough I had frozen after I finished baking over 1500 miniature heart-shaped cookies (half vanilla, half chocolate) to fill the favor bags for my daughter's wedding last month.
The recipe below is adapted from the one in Mark Bittman's How to Cook Everything. I had to come up with my own chocolate variation; I couldn't find one anywhere. Christine's colors were black and white with red as an accent. The chocolate cookies would have been darker if I had used "black" cocoa powder, but it's hard to find and I didn't think about it in time to mail-order it.
Vanilla Shortbread Hearts
2 sticks (8 ounces) unsalted butter, softened
3/4 (6 ounces) cup sugar (I used superfine)
1 egg yolk
1/2 teaspoon real vanilla extract
1 1/2 (7 ounces) cups all-purpose flour
1/2 cup (2.5 ounces) cornstarch
pinch of sea salt
Cream together the softened butter and sugar with an electric mixer on the low setting. Add the egg yolk and vanilla and mix until well-combined. In a separate bowl, stir together the flour, cornstarch, and sea salt. Add to the butter mixture and mix in just until it holds together. Divide in half, press into a disc, wrap in plastic wrap, and chill several hours or overnight. Alternatively, you can roll each half out to the desired thickness (1/8 to 1/4 inch) between two sheets of waked paper and freeze in a 2-gallon ziploc bag. It's very easy to peel off the waxed paper, place the dough on a lightly floured board and cut into shapes.
When ready to bake, preheat the oven to 275 degrees. Line a cookie sheet with parchment. Roll out dough to desired thickness (if you didn't freeze it that way you'll need to let it soften about 30 minutes) and cut into shapes.
Bake for 20 to 25 minutes, depending on the thickness. Do not let the cookies brown. Remove from oven and let cool on cookie sheet for one minute. Transfer to a wire rack and let cool completely.
If you have a convection oven, you can bake three sheets at a time for 15 to 19 minutes.
Chocolate variation: Same as above but increase sugar to 1 1/4 cups and add 1 ounce melted and cooled dark chocolate (I used Ghirardelli 60% Cacao chips) to the butter mixture. Add 1/4 cup (1 ounce) cocoa powder with the flour.
To dip the hearts in chocolate, use the recipe for Chocolate-dipped Strawberries.