1 cup granulated sugar
1 cup packed light brown sugar
1 cup unsalted butter, melted
2 large eggs at room temperature
1-1/2 teaspoons vanilla extract
2 cups all-purpose flour
1 cup old-fashioned oats
1/2 teaspoon salt
1/2 teaspoon baking soda
1/2 teaspoon cinnamon
1 cup white chocolate chips
1 cup semisweet chocolate chips
Test Kitchen Tip: To keep as much moisture in the butter as possible, melt it over low heat or in short bursts in the microwave just until it liquefies.
Step 1: Combine the wet ingredients
Beat together the granulated and brown sugars with the melted butter, using a stand or hand mixer on medium speed until the ingredients are blended. Pop this mixture into the fridge for 10 minutes to cool it down.
Next, beat the eggs one at a time into the butter-sugar mixture, blending them in very well after each addition. Mix in the vanilla extract.
Step 2: Add the dry ingredients
Mix together in a separate bowl the flour, oats, salt, baking soda and cinnamon. Add the dry mixture into the wet ingredients gradually, with the mixer running at medium-low speed. Finally, stir the white chocolate and semisweet chocolate chips into the batter. Scrape the bowl well to catch any unmixed pockets at the bottom of the bowl.
Step 3: Scoop and chill
Line two large baking sheets with parchment paper. Use a quarter-cup-sized cookie scoop or measuring cup to scoop the dough. (If you have a kitchen scale, the portions should weigh about 2.5 ounces.) Place the scoops on the baking sheet spaced two inches apart. Place the baking sheets into the fridge to chill the dough for 30 minutes. While it chills, preheat the oven to 325°F.
Tip: Don’t skip this important chilling step. It firms up the melted butter in the batter and prevents the cookies from spreading too thin during baking.
Step 4: Bake
Place the baking sheets in the preheated oven and bake the cookies for 18 to 20 minutes. If you have two baking sheets in the oven at once, swap them around halfway through baking so that the cookies bake evenly. When the cookies are done they’ll be set and lightly browned around the edges, and the centers will look soft and almost underbaked.
Let the cookies cool on the baking sheets for two minutes to make them easier to move. Then, use a spatula to carefully transfer them to a cooling rack.