Adapted from Fine Cooking
1 1/3 cups flour
1/2 teaspoon salt
1/2 teaspoon baking powder
1/4 teaspoon baking soda
1 stick (4 ounces) butter, at room temperature
1 1/3 cups sugar
1/2 cup cocoa powder, sifted
1 teaspoon vanilla
3 ounces semisweet chocolate, melted and cooled slightly
For the chocolate filling:
3 ounces semisweet chocolate, coarsely chopped (1/2 cup)
4 tablespoons butter, cut into 3 pieces
OR use Caramel Kisses*
M and M's, optional garnish
Preheat the oven to 350°. Line cookie sheets with parchment and set aside.
In a medium bowl, whisk the flour, salt, baking powder, and baking soda.
Using a mixer, beat the butter, sugar, and cocoa powder on medium speed until well blended, about 2 minutes. Add the eggs one at a time, mixing until blended after each addition, then mix in vanilla. Add the cooled, melted chocolate and mix till combined, then add flour mixture. Mix just till incorporated.
Place tablespoons of dough about 1-1/2 inches apart on the cookie sheets. Bake till the cookies are puffed and crackled, about 8-10 minutes.
When the cookies are just out of the oven, and you plan to use the ganache filling, use the rounded side of a half-teaspoon measuring spoon, make a deep well in the center of each cookie. Let the cookies sit on the cookie sheet for 4-5 minutes before moving to a rack to finish cooling.
*If using Kisses, cool cookies 4-5 minutes, then press unwrapped Kiss into center of each cookie.
To make the filling, melt the chocolate and butter in the microwave, stirring with a rubber spatula until smooth. Set aside until cool and slightly thickened.
Spoon the chocolate mixture into the wells of the cooled cookies. Place an M and M in the center of the ganache, if desired. Set aside until the chocolate firms up, about 1 hour.