⅓cupturbinado sugar(sanding sugar or granulated sugar may be substituted)
6ounces (chopped bittersweet or semi-sweet chocolate
2tbspheavy whipping cream
1package (11 oz or 311 g)Hershey's kisses, unwrapped(or enough unwrapped kisses to fill 40-50 cookies)
In a large bowl, cream butter and both sugars until fluffy, about 2 minutes. Add egg yolks and vanilla and beat until well combined. Scrape down sides of bowl.
In a separate bowl, mix together flour, baking powder, and salt. With the mixer running on low, slowly add flour mixture into butter mixture until well blended. Cover the bowl and refrigerate until the dough is firm, about 30 minutes.
Place the turbinado sugar in a small shallow bowl. Shape the dough into 1-inch balls and roll each in the sugar to coat. Place 1 inch apart on a parchment-lined baking sheet. If using homemade ganache, press your thumb in the center of each ball to make a crevice. If using Hershey's kisses, skip this part and leave the dough in balls.
Bake cookies in a 325° F oven until lightly browned, about 10-12 minutes. If the indentations have disappeared, make them again while the cookies are still warm. If using Hershey's kisses, press a kiss in the center of each cookie as soon as they come out of the oven.
Make the Chocolate Ganache
While the cookies are baking, make the ganache. In a double boiler (a heat-proof bowl set over a pan of simmering water), melt chocolate with heavy cream, corn syrup, and butter, stirring gently until all the chocolate is melted and the mixture is smooth. Allow the ganache to cool for 10-15 minutes.
Filling the Cookies
Fill each cookie with about a teaspoon of chocolate ganache. It will harden like a chocolate chip (or Hershey's kiss) when it cools.
Cookies freeze very well for up to 2 months. Wrap well before freezing, and leave wrapped when thawing.