Oatmeal and Turbinado Cream Cookie Sandwiches
Makes: 15, 2½-inch cookies
Oatmeal Cookies:
  • 1½ cups (5¼ ounces/150 grams) old- fashioned rolled oats
  • 1 cup (8 ounces/227 grams) firmly packed dark muscovado sugar
  • ½ cup (4¼ ounces/120 grams) whole wheat pastry flour, spooned and leveled
  • ½ teaspoon fine sea salt
  • ½ teaspoon baking soda
  • ¼ teaspoon baking powder
  • ½ teaspoon ground cinnamon
  • ¼ teaspoon freshly grated nutmeg
  • ½ cup (1 stick/4 ounces/113 grams) cold unsalted butter, cut into cubes
  • 1 large egg yolk - save the egg white for the filling!
Turbinado Cream Filling:
  • ⅔ cup (4⅝ ounces/132 grams) turbinado sugar
  • 3 large egg whites
  • ¼ teaspoon fine sea salt
  • ½ cup (1 stick/4 ounces/113 grams) butter, cut into ½-inch cubes, soft but still cool
  • 1 teaspoon pure vanilla extract
  1. Make the cookies: In the bowl of a food processor fitted with the steel blade, grind the oats to a flour. Add the muscovado sugar, flour, salt, baking soda, baking powder, cinnamon, and nutmeg and process briefly to blend.
  2. Toss in the butter and process until the butter is well incorporated and the dough begins to clump and pull off the sides of the bowl. Add the egg yolk and pulse until the dough comes together with no dry pockets.
  3. Line a work surface with a large sheet of plastic wrap. Turn out the dough onto the plastic wrap and form it into a log about 10 inches long and 1½ inches in diameter. Wrap the dough tightly. Chill the dough until firm, at least 3 hours in the refrigerator.
  4. When you’re ready to bake, position a rack in the center of the oven and preheat the oven to 350˚F. Line 2 baking sheets with parchment paper. Use a thin, sharp knife to slice the dough log into 30 rounds, each about ⅓ inch thick. Transfer the rounds to the prepared baking sheets. Bake until golden and firm, about 15 minutes. Transfer the cookies to a wire rack to cool completely.
  5. Make the filling: Combine the turbinado sugar, egg whites, and salt in the metal bowl of a stand mixer. Set the bowl over a pan of gently simmering water. Whisk until the mixture is slightly foamy and the sugar has completely dissolved—rub a bit of the mixture between your fingertips to make sure no coarse bits of sugar are lurking in the bottom of the bowl. Attach the bowl to the mixer fitted with a whisk attachment. Beat on high speed until the meringue is stiff and glossy and the bowl is cool to the touch, 8 to 10 minutes depending on your mixer.
  6. Reduce the speed to medium and beat in the butter a tablespoon at a time, giving each knob of butter ample time to incorporate into the filling before adding the next. About the time that all the butter has been added, the filling will look like a curdled and separated mess and you might start to panic, but don’t—it will come together with another minute or so of whipping time. When the filling is smooth, beat in the vanilla extract. (Hooray, you’ve just made Swiss meringue buttercream!)
  7. To fill the cookies, either load the filling into a piping bag fitted with a large round tip, or use a small scoop or 2 spoons. Flip half the cookies over and top each with 2 teaspoons of the filling. Sandwich with the remaining cookies and press gently to adhere. Store at room temperature for the first day, and refrigerate them for longer storage, up to 3 days.
Recipe by Bakepedia at https://www.bakepedia.com/oatmeal-and-turbinado-cream-cookie-sandwiches/