Claire just described these cookies as the best cookies ever. The recipe is a slight variation on a Martha recipe from her Cookies cookbook (which I've recommended in past posts). I think there are two key tips to making these cookies: turn the cookie sheets halfway through baking (switching their positions on oven racks if appropriate) and cool the cookies on the cookie sheets on top of wire racks for 2 minutes before moving them to the racks to fully cool.
Christie Family Chocolate Cookies (makes 3-4 dozen cookies)
1 cup all-purpose flour
1 1/4 cups whole wheat flour
1/2 teaspoon baking soda
1 cup (2 sticks) unsalted butter, room temperature
1/2 cup granulated sugar
3/4 cup packed light-brown sugar
1 teaspoon salt
2 teaspoons pure vanilla extract
2 large eggs
1 1/2 cups semisweet and/or milk chocolate chips
Preheat oven to 350 degrees. In a small bowl, whisk together the flours and baking soda; set aside. In the bowl of an electric mixer fitted with the paddle attachment, combine the butter with both sugars; beat on medium speed until light and fluffy, about 2 minutes. Reduce speed to low; add the salt, vanilla, and eggs. Beat until well mixed, about 1 minute. Add flour mixture; mix until just combined. Stir in the chocolate chips.
Drop heaping tablespoon-size balls of dough about 2 inches apart on baking sheets lined with parchment paper.
Bake until cookies, rotating sheets halfway through, until they are golden around the edges, but still soft in the center, 8 to 10 minutes. Remove from oven, and let cool on baking sheet 1 to 2 minutes. Transfer to a wire rack, and let cool completely. Store cookies in an airtight container at room temperature up to 1 week.