Shortbread Cookie Bars - Bake from Scratch

      These Shortbread Cookie Bars are particularly tender and have a melt-in-your-mouth quality due to a crucial substitution: using confectioners’ sugar instead of granulated sugar. Since it dissolves immediately in softened butter, confectioners’ sugar results in a very smooth dough and a finer, more delicate crumb. Like most shortbread varieties, the dough is easy to combine—there's no need for chilling or rolling. You simply press it into the pan, which reduces gluten formation and gives you that classic sandy texture. Docking the dough with a fork serves a purpose beyond aesthetics; it allows steam to escape, promoting even baking without any puffing in certain areas.

      **Shortbread Ingredients:**

      - 1½ cups (340 grams) salted butter, softened

      - 1 cup (120 grams) confectioners’ sugar

      - 1 tablespoon (13 grams) vanilla extract

      - 3 cups (375 grams) all-purpose flour

      - 1 teaspoon kosher salt

      **Buttercream Ingredients:**

      - 1 cup (227 grams) salted butter, softened

      - 4 cups (480 grams) confectioners’ sugar

      - ½ teaspoon kosher salt

      - 2 tablespoons (30 grams) whole milk

      - 2 teaspoons (8 grams) vanilla extract

      **Garnish:**

      - assorted sprinkles

      Preheat the oven to 325°F (170°C). Line an 8-inch square baking pan with parchment paper, allowing excess to hang over the edges. For the shortbread, in the bowl of a stand mixer fitted with the paddle attachment, mix the butter and confectioners’ sugar on medium speed until creamy, which should take 3 to 4 minutes, pausing to scrape down the bowl. Then, mix in the vanilla. In another bowl, combine the flour and salt using a whisk. With the mixer on low speed, gradually incorporate the flour mixture into the butter mixture, mixing until a cohesive dough forms, while also scraping the bowl's sides and bottom. Press the dough into the lined pan, and prick the surface with a fork.

      Bake for 30 to 35 minutes, or until the edges are lightly browned and an instant-read thermometer inserted in the center reads between 200°F (93°C) and 205°F (96°C). Allow it to cool completely in the pan on a wire rack.

      For the buttercream, using the stand mixer with the paddle attachment, beat the softened butter on medium speed until creamy, about 1 to 2 minutes. Then, with the mixer on low speed, gradually add the confectioners’ sugar and salt, beating until smooth while scraping the bowl's sides and bottom as necessary. Mix in the milk and vanilla, beating until fully combined and smooth, again scraping the sides of the bowl as needed. Increase the mixer speed to high and beat the mixture until it becomes light and fluffy, which should take about 2 minutes.

      Spread the buttercream over the chilled shortbread. If desired, top with sprinkles. Using the overhanging parchment as handles, lift the shortbread out of the pan and cut it into bars. Store in an airtight container for up to 3 days.

      We'd love to hear how it turned out!