To know Rebecca Firth, mastermind behind the blog DisplacedHousewife, is to know cookies. So it should come as no surprise that her new cookbook, The Cookie Book, has more than 75 recipes for every step along the cookie spectrum—including this one for what she calls a "lemon bar's long-lost cousin." Look for lemongrass wherever you find herbs at your grocery store, but if you can't find it, Firth says you can just omit it; there's enough zesty lime flavor to pick up the slack.
Thai Lemongrass Lime Bars
Reprinted with permission from The Cookie Book by Rebecca Firth, Page Street Publishing Co. 2018
Yield: 18 bar cookies
Prep Time: 25 minutes, plus cooling time
Cook Time: 45 minutes
Total Time: 1 hour and 10 minutes, plus cooling time
For the Crust:
2 cups all-purpose flour
⅓ cup granulated sugar
¼ cup cornstarch
¼ cup unsweetened shredded coconut
1 tablespoon lime zest (about 1 large lime)
1 tablespoon fresh mint, finely chopped
1 teaspoon sea salt
20 tablespoons (2½ sticks) unsalted butter, cut into 20 pieces, room temperature
For the Filling:
2 cups granulated sugar
¼ cup fresh lemongrass, chopped
4 tablespoons powdered sugar
5 large eggs, room temperature
1 large egg yolk, room temperature
¾ cup fresh lime juice (4 to 5 limes)
2 tablespoons lime zest (2 limes)
¾ cup all-purpose flour
1 tablespoon fresh whole mint leaves
4 tablespoons unsalted butter (½ stick), cut into 4 pieces, room temperature
¼ cup powdered sugar, to garnish
1. For the crust, preheat your oven to 350°F. Grease a 9 x 13–inch casserole dish and line with parchment paper, letting the excess fall over
2. In a food processor fitted with the blade attachment, add the flour, sugar, cornstarch, coconut, lime zest, mint and salt and pulse several times to mix. Sprinkle the butter over the flour mixture and run the processor for 1 minute, or until a ball starts to form. Press the dough evenly and firmly into the bottom of the casserole dish. Bake in the middle of the oven for 30 minutes or until the sides are lightly bronzed. Set aside to cool completely.
3. To make the filling, place the granulated sugar and lemongrass in a food processor and run the machine for 1 to 2 minutes or until the lemongrass is reduced to small bits. Add in the powdered sugar, eggs, egg yolk, lime juice, lime zest and run the machine for 1 minute more or until combined. Add in the flour and mint leaves and run the machine for 15 to 30 seconds. Strain the mixture into a medium heavy-bottomed saucepan over medium heat. Add the butter and whisk for 6 to 8 minutes or until thickened. If it develops any lumps, strain one more time before pouring over the cooled crust.
4. Bake for 15 minutes in the center of the oven. Let the bars cool and then cover and place in the fridge for several hours to set completely.
5. Pull the bars out of the pan using the excess parchment paper and set on a cutting board. Sift powdered sugar over the top. Cut into squares, cleaning your knife between cuts.