Step 1

Line two large baking sheets with parchment papers. Stir together all-purpose flour, whole-wheat flour, baking powder and baking soda in a bowl. Set aside.

Step 2

Cream together butter, brown sugar, granulated sugar in a stand mixer fitted with a paddle attachment on medium speed until smooth, about 1 minute. Add eggs and vanilla; beat 2 minutes. Gradually add flour mixture, beating until combined, about 30 seconds. Gently fold in chocolate chips using wooden spoon or rubber spatula.

Step 3

Divide dough evenly into 12 balls. Arrange 6 balls on each baking sheet, leaving 2 inches between each ball. DO NOT FLATTEN. Sprinkle each ball lightly with sea salt flakes. Cover and chill overnight, or freeze 15-20 minutes.

Step 4

Preheat oven to 375°F (190°C). Uncover cookie dough and bake cookies until edges are golden brown, 20-22 minutes. Let cool on baking sheet for 5 minutes. Transfer the cookies to a wire rack to cool completely. Store in an airtight container at room temperature for up to a week.