Key Lime Pie Thumbprint Cookies

Instructions

1. Place racks in upper and lower thirds of oven and preheat to 350°. Pulse 9 graham cracker sheets (about 5 oz.; 1 sleeve) in a food processor until sandy crumbs form. Add ¾ cup plus 1 Tbsp. (101 g) all-purpose flour and 1¼ tsp. Diamond Crystal or ¾ tsp. Morton kosher salt; pulse to combine. Transfer to a small bowl.

2. Pulse ½ cup (packed; 100 g) light brown sugar and ½ cup (1 stick) unsalted butter, room temperature, in processor until creamy. Add 1 large egg and ½ tsp. vanilla extract and pulse just to combine. Add graham cracker mixture and process until dough comes together and forms a ball, about 45 seconds.

3. Place ¼ cup (50 g) granulated sugar in a clean small bowl. Using a #40 cookie scoop (about 2 Tbsp.), portion out dough; roll into smooth balls (dough will be sticky). Working one at a time, toss balls in granulated sugar to coat generously. Divide between 2 parchment-lined baking sheets, spacing at least 2" apart (about 7 per sheet). Working one at a time, dip the bottom of a shot glass or ⅛-cup measuring cup into remaining granulated sugar, then press down in center of balls to create a divot that can hold 2 tsp. filling, about ¼" deep (for the first cookie, press glass into it a little before dipping into sugar; it will easily adhere to glass from thereafter). Chill cookies in freezer 15 minutes.