Preheat oven to 350 degrees F. Butter a 12 1/2-inch) heart-shaped cake pan. Dust the bottom and sides with flour; tap to remove any excess. Set aside. In a medium bowl, whisk together the flour, baking soda, and salt; set aside.
In a large bowl using a wooden spoon, combine the butter, both sugars, and vanilla; beat until fluffy, about 5 minutes. Add the egg, and mix until combined. Add the reserved dry ingredients and mix until just combined. Stir in the chocolate chips.
Using your fingers, press dough into the bottom of the prepared pan in an even layer. Bake until light golden brown, about 25 minutes. Transfer to wire rack to cool, about 10 minutes. Invert pan to release cookie and return to wire rack to cool completely, top side up. Allow to cool completely before decorating.
Transfer ganache to a medium pastry bag fitted with an Ateco plain #7 tip. Pipe desired decoration onto cookie.
Place chocolate chips in a medium bowl. Set aside. Place heavy cream in a saucepan over medium heat. Bring to a simmer. Pour half of the heavy cream over chocolate chips, let sit for 1 minute. Whisk gently to smooth. Add remaining half of cream' whisk gently until just combined. Leave out at room temperature, stirring frequently until the consistency of toothpaste, about 1 hour.
Yield: 1 1/2 cups
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