3 cups all-purpose flour
1 1/2 teaspoons baking soda
1 1/2 teaspoons salt
2 sticks (1 cup) unsalted butter, melted and cooled slightly
1 1/2 cups packed light brown sugar
1 cup granulated sugar
3 large eggs
1 1/2 teaspoons vanilla
2 cups semisweet chocolate chips (12 oz)
Put oven rack in middle position and preheat oven to 375°F. Line 2 large baking sheets with parchment or wax paper.
Whisk together flour, baking soda, and salt in a small bowl.
Beat together butter and sugars in a large bowl with an electric mixer at high speed until pale and fluffy, 2 to 3 minutes. Lightly beat 1 egg with a fork in a small bowl and add 1 3/4 tablespoons of it plus 2 remaining whole eggs to butter mixture, beating with mixer until creamy, about 1 minute. Beat in vanilla. Reduce speed to low and mix in flour mixture until just blended, then stir in chips.
Scoop 1/4 cup batter for each cookie, arranging mounds 3 inches apart, on 2 baking sheets. Flatten mounds into 3-inch rounds using moistened palm of your hand. Form remaining cookies on additional sheets of parchment.
Bake, 1 sheet at a time, until golden, 13 to 15 minutes. Transfer cookies to a rack to cool and continue making cookies in same manner using cooled baking sheets.