Recipe by Karen DeMasco

Ingredients

For the cookies:

• 4 tablespoons (1/2 stick) cold unsalted butter plus 12 tablespoons (1 1/2 sticks) unsalted butter, at room temperature
• 1 cup rolled oats (preferably Quaker)
• 3/4 cup Nutella
• 1/2 cup packed dark brown sugar
• 1/2 cup granulated sugar
• 2 cups unbleached all-purpose flour plus more for dusting
• 2 teaspoons baking soda
• 2 teaspoons kosher salt
• 1/4 cup Demerara sugar (see Note)

For the filling:

• About 1 cup Nutella

Special equipment: parchment paper

Instructions

For the cookies: Heat oven to 350º. Line 3 baking sheets with parchment paper.

In a large skillet, melt 4 tablespoons cold unsalted butter over medium heat. Add oats and cook, stirring frequently, until fragrant and lightly golden, about 5 minutes; transfer oats to a large metal bowl and set aside.

In the bowl of an electric mixer fitted with the whisk attachment, combine room temperature butter, Nutella, brown sugar and granulated sugar. Beat on medium speed, frequently scraping down the sides of bowl, until fluffy and well combined, 3 to 4 minutes.

In a separate bowl, whisk together flour, baking soda and salt. In two additions, add flour mixture to butter mixture, mixing on low speed until well incorporated, then add oats and mix until dough comes together and oats are incorporated.

Lightly flour the palms of your hands. Scoop 1 level tablespoon dough, roll into a ball, then flatten to about 1/8-inch-thick. Place on a prepared baking sheet. Repeat with remaining dough, spacing cookies at least 1 inch apart. Sprinkle with Demerara sugar. Bake, rotating the pans halfway through, until the cookies are puffed and golden, 12 to 15 minutes. Transfer cookies on parchment paper to wire racks to cool completely. (Cookies can be stored, unfilled, in an airtight container at room temperature for up to 3 days.)

To fill the cookies: Using an offset spatula or butter knife, spread about 1 tablespoon Nutella over the flat sides of half of the cookies. Sandwich with remaining cookies, flat sides together.

Once filled, cookies are best same day, but can be kept in an airtight container at room temperature for up to 2 days.

Note: Demerara is a natural brown sugar, an English version of turbinado sugar but with a slightly larger crystal size. When sprinkled on cookies and pie crusts, it adds sparkle and crunch. Turbinado is a good substitute while granulated sugar will work in a pinch.