Instructions
Step 1
Make the cake: Preheat the oven (with one of its racks positioned in the center) to 350°F. Line a very flat, 18- by 13-inch rimmed baking sheet with parchment paper and set aside.
Step 2
In a medium bowl, whisk together the flour, baking powder, and salt. In the bowl of a stand mixer fitted with the whip attachment, beat the eggs, sugar, and honey on medium speed until thoroughly combined and creamy, about 1 minute. Using a silicone spatula, fold the dry ingredients into the egg mixture until completely combined. Pour the batter into the lined baking sheet and, using an offset spatula or the back of a spoon, smooth the batter into a very even layer. Transfer to the oven and bake, rotating the tray once halfway through cooking, until a toothpick inserted into the middle of the cake comes out clean, 10–12 minutes. Remove from the oven and set aside to cool completely to room temperature.
Step 3
Using a 2¼-inch round cookie cutter, punch out 24 circles of cake, handling carefully to avoid crumbling. Using a piping bag or a large spoon, top half of the circles with 2 generous tablespoons of dulce de leche and a teaspoon of crushed pecans each. Top the dulce- de leche-topped rounds with their mates and gently squeeze together to make tall sandwiches. Use a small offset spatula or butter knife to smooth any excess filling, creating a uniform border so that the dulce de leche is flush with the edges of the cake.
Step 4
Make the meringue glaze: Set a small pot fitted with a candy thermometer over medium-low heat, then add the sugar, lemon zest, and ⅓ cup water, stirring gently to dissolve the sugar.
Step 5
In the bowl of a stand mixer fitted with the whip attachment, beat the egg whites at medium-high speed until medium-stiff peaks begin to form. Turn the heat under the pot of lemon syrup up to medium and cook until it reaches 245°F. With the mixer running, slowly drizzle the hot syrup into the beaten whites in a steady stream, then increase the mixer speed to medium-high and continue beating until the meringue cools to room temperature, is fluffy and glossy, and holds stiff peaks, 5–7 minutes.
Step 6
Finally, glaze the marplatense: Place a small bowl of confectioners’ sugar by your work space and line a large baking sheet with a wire rack. Using a small offset spatula or butter knife, frost the alfajores all over with the meringue, finally dipping the cakes on one of the flat sides in the confectioners’ sugar to prevent sticking. Place the alfajores sugar-side-down on the rack and set aside until the meringue is slightly dry to the touch, 4–6 hours. Serve immediately, or transfer to an airtight container and store at room temperature for up to 2 weeks.