HAZELNUT LACE SANDWICH COOKIES

Steps:

• Cookies:
• Pulse hazelnuts, flour, and salt in a food processor until nuts are finely ground; set aside.
• Cook butter in a medium saucepan over medium heat until butter foams, then browns, about 5 minutes. Let cool about 5 minutes, then add granulated sugar, cream, maple syrup, vanilla, and 1 Tbsp. water and stir to incorporate. Return saucepan to medium heat and bring to a boil; cook, without stirring, 30 seconds. Remove pan from heat and stir in hazelnut mixture. Scrape batter into a medium heatproof bowl and let cool, stirring occasionally to reincorporate the butter.
• Meanwhile, place racks in upper and lower thirds of oven; preheat to 325°F.
• Scoop out rounded teaspoonfuls of batter and roll between the palms of your hands into smooth balls. Place on 2 parchment-lined baking sheets at least 3" apart. Because these cookies spread so much during baking, give each ball plenty of space. You should be able to fit 8 per sheet and will need to bake in 2 batches for a total of 32 cookies.
• Bake cookies, rotating baking sheets top to bottom and front to back halfway through, until they spread into thin lacy disks and are deep golden brown around the edges, 10-14 minutes. Let cool on baking sheets. Repeat with remaining batter, using fresh parchment paper on baking sheets.
• Filling and assembly:
• Using an electric mixer on medium speed, beat butter in a medium bowl until light, about 1 minute. Add powdered sugar and beat until pale, about 30 seconds. Add jam about 1 tablespoonful at a time, beating until smooth after each addition, then beat in lime zest.
• Carefully remove cooled cookies from parchment. Using a small offset spatula, spread 1-2 tsp. filling across flat sides of half of cookies. Top with remaining cookies to create sandwiches.
• Do Ahead
• Cookies can be baked 2 days ahead. Store airtight at room temperature, separated by layers of parchment paper to prevent sticking.