Preheat oven to 375°F. In a medium bowl, stir together all cookie ingredients. Divide the dough into 12 equal balls of cookie dough and set 2 inches apart on an ungreased cookie sheet.

Bake 12 minutes. Let cool completely.

Place the dark chocolate in one small bowl, and the white chocolate in a different small bowl. In a microwavable measuring cup, heat the heavy cream for 45 seconds to 1 minute, or until the cream is starting to bubble.

Pour 1/2 cup heavy cream over the dark chocolate and the remaining 1/4 cup heavy cream over the white chocolate. Let stand for 30 seconds, and then stir each until smooth.

Let cool for 15-20 minutes or until slightly thickened. Spread the dark chocolate ganache on top of all the cookies. Place the white chocolate ganache in a Ziploc bag and snip the corner. Draw a series of concentric circles on one of the cookies, on top of the chocolate ganache. Use a toothpick to draw lines coming out from the center of the circles, forming a spider web shape. Repeat for all of the cookies.

Let chocolate ganache cool completely before serving.