Macaroon Sandwich Cookies

Ingredients

• ½ cup sweetened condensed milk
• ½ teaspoon vanilla extract
• 2¼ cups sweetened shredded coconut
• 1 large egg white
• ¼ teaspoon kosher salt
• ½ cup filling of your choice (such as raspberry or sour cherry jam, chocolate ganache, lime or lemon curd or dulce de leche)

Directions

1. Preheat the oven to 350°. Line 2 rimmed baking sheets with parchment paper. To a large bowl, add the condensed milk and vanilla and stir together using a rubber spatula. Add the shredded coconut and stir until well combined.
2. To the bowl of a stand mixer fitted with the whisk attachment, add the egg white and salt. Whip on medium-high speed until very stiff peaks form, 2½ to 3 minutes. Fold the beaten egg whites into the coconut mixture, gently stirring and "pushing" the mixture until it forms into a cohesive mass.
3. Fill a small bowl with water. Lightly wet your hands then form a small bit of the dough into a ½-inch ball. Place the ball on a parchment-lined baking sheet. Repeat enough times to fill both baking sheets, spacing the balls about 3 inches apart, and continuing to wet your hands to keep them from getting too sticky (you'll have enough dough leftover for one more sheet of 12 cookies). Dip a spoon in the cold water and use the back of it to press each ball into a thin disk, so, when flattened, it measures about 2 to 2½ inches wide.
4. Reduce the oven temperature to 325° and bake the cookies until they are very pale golden with barely golden edges, 10 to 12 minutes, rotating the baking sheets from top to bottom and back to front midway through baking.
5. Remove the cookies from the oven and set aside on the baking sheets to cool. Increase the oven temperature to 350°. Once the cookies are set and cool enough to handle, use a butter knife or small offset spatula to separate the cookies from the parchment, then bake off the remaining cookie dough. (Once cooled, the cookies can be stored in an airtight container for up to 5 days or frozen for up to 6 months.) 6. Turn half of the cookies upside-down. Add a generous teaspoon of filling to each cookie bottom and sandwich with another cookie on top. Repeat with the remaining cookies and filling.