Preheat the oven to 350 degrees F with 1 rack in top third and 1 rack in bottom third of oven. Line baking sheets with parchment paper or nonstick baking mat; set aside.
Plump dried cherries; cover with boiling water and let stand 5 minutes. Drain and set aside.
In the bowl of an electric mixer fitted with a paddle attachment, combine butter and sugars. Beat on medium speed until light and fluffy, about 2 minutes. Scrape down sides of the bowl. Add egg and vanilla extract and beat to combine. Beat in flour, baking soda, and salt. Mix in cherries, white and milk chocolate, and pecans. Batter should be stiff.
Use a large (2 1/2-ounce) or small (1 1/4-ounce) ice-cream scoop to form balls of the dough. Place the balls of dough about 4 inches apart on the baking sheets. Bake until golden and just set, rotating the sheets between the oven racks halfway through baking to ensure even browning, about 15 minutes for large cookies and 12 minutes for small cookies. Transfer the sheets to a wire rack to cool about 5 minutes before transferring the cookies to the rack. Store in an airtight container up to 1 week.
(c)2004 Martha Stewart Living Omnimedia, Inc. All Rights Reserved.