2 cups all-purpose flour
⅔ cup nonalkalized cocoa powder
1 tsp baking powder
½ tsp baking soda
⅛ tsp salt
¾ cup (1½ sticks) unsalted butter, softened
1⅓ cups granulated sugar
2 large eggs
1½ tsp vanilla
⅔ cup sour cream
1 cup semisweet chocolate chips
4 oz white chocolate
Preheat oven to 350°F.
Sift together the flour, cocoa powder, baking soda and salt into a medium bowl. Gently whisk to blend.
Beat the butter and sugar at medium speed until light, about 2 minutes. Add the eggs, one at a time, beating well after each addition and scraping down the sides of the bowl if necessary. Mix in the vanilla extract. At low speed, add the dry ingredients in three additions, alternating them with the sour cream in two additions, and mixing until just combined. Using a wooden spoon, stir in the chocolate chips.
Drop the dough by tablespoonfuls onto prepared baking sheets, spacing the cookies 1 inch apart. Bake the cookies, one sheet at a time, for 12 to 15 minutes, or until no impression is left when you touch a cookie very lightly with a finger. Transfer the cookies to a wire rack and cool completely. Makes about 72 cookies.
Melt white chocolate over barely simmering water, stirring frequently. Scrape the white chocolate into a small sealable plastic bag. Using scissors cut a tiny hole in one of the bottom corners of the bag.
Drizzle the chocolate over the cookies in thin parallel lines. Refrigerate cookies for 5 minutes, or just until the chocolate is set.
Source: The Good Cookie by Tish Boyle, 2002