Preheat the oven to 325°F. Line cookie sheets with parchment paper (or spray with nonstick spray).
In a medium bowl, sift together the flour, baking soda and salt. Set aside.
In a separate bowl, use an electric mixer to combine the melted butter and sugars until well mixed. Beat in the egg, egg yolk and vanilla until light and creamy. Add the dry ingredients and stir until just blended. Stir in the chocolate with a firm spoon.
Drop tablespoonfuls of cookie dough onto the cookie sheets with a small cookie scoop, if you have one. Be sure to leave room for them to spread (about 2 inches apart).
Bake for 12 to 15 minutes, or until the edges are lightly browned. Cool on baking sheets for a few minutes before transferring to wire racks to cool completely.
Notes
*If you don't care for white chocolate, use all bittersweet (2 cups).
*These cookie freeze well. Just drop onto cookie sheets with a rounded tablespoon. Place the cookie sheet directly into the freezer. Remove when frozen solid and transfer the frozen cookie dough to freezer zip baggies. When ready to bake, just follow baking instructions. They are just as good as when baked fresh.