Zesty Key Lime Macarons Recipe

If you're looking for an indulgent treat to transport you right to the tropics, these key lime macarons are it. In this recipe, the crisp, delicate shells of classic French macarons are paired with a luscious, tangy key lime curd, delivering a bright and zesty bite.

Whether you're a seasoned baker or new to macarons, this recipe simplifies the process. Recipe developer Katie Rosenhouse uses a French meringue method, explaining, "When I'm teaching someone to make macarons for the first time, I try to take the most straightforward route I can. In this recipe, there's no sugar syrup to cook, and everything is folded together in one go. It doesn't get easier than that."

This refreshing twist on a beloved confection is ideal for summer celebrations, special occasions, or for adding a bit of brightness to a winter day. They're vibrant in flavor and color, bringing a burst of sunshine to any dessert table.

To make these zesty key lime macarons, you'll need some simple ingredients. For the filling, you'll need egg yolks, a whole egg, granulated sugar, key lime juice, lime zest, and kosher salt. The lime zest brings a bright punch of flavor, so don't skip it. You can even fold some zest into the macaron shells for extra citrusy notes. While key lime juice offers a distinctive tang, standard lime juice or a mix of lemon and lime can work in a pinch. If you're lucky enough to have fresh key limes, their juice will elevate the flavor even more. Butter is the final touch, adding richness and a silky texture that helps the curd firm up beautifully in the fridge. 

For the macaron shells, you only need five ingredients. Super fine blanched almond flour and confectioners' sugar create the base of the cookie — just make sure your almond flour is finely ground to keep the shells smooth. Room temperature egg whites are best for creating volume, with sugar added to whip up a glossy meringue that sweetens and lightens the cookies. A bit of green gel food coloring gives the shells their classic key lime hue.

For a finishing touch, you can sprinkle the filled macarons with lime zest and a light dusting of confectioners' sugar before serving.

Prepare the filling: In a small pot, whisk to combine the egg yolks, whole egg, sugar, key lime juice, zest, and salt.

Cook over medium heat, whisking constantly, until mixture thickens and starts to bubble up. Remove from heat.

Add butter and whisk until melted.

Transfer the filling to a small bowl. Cover with plastic wrap directly on the surface and refrigerate for at least 1 hour or until thickened and cold.

Prepare the macarons: Line two rimmed baking sheets with parchment paper.

Preheat the oven to 325 F.

In a medium bowl, sift to combine almond flour and confectioners' sugar; set aside.

In the bowl of a stand mixer fitted with a whisk attachment, whip egg whites until frothy.

Add sugar and whip to soft peaks.

Add food coloring to reach desired shade of green, then whip to medium peaks.

Pour almond flour mixture over meringue. Fold with a rubber spatula until mixture reaches a lava-like consistency.

Prepare a large piping bag with a medium round tip. If desired, draw a few lines of food coloring inside the bag.

Fill the bag with the macaron batter.

Pipe 1 ½-inch rounds of batter onto the prepared baking sheets, spacing them at least ½-inch apart.

Bake for 10 to 12 minutes, until the macarons release from the baking sheet and are firm to the touch (but still soft in the center). Set aside to cool completely.

When the macarons are cool and the filling is chilled, transfer key lime curd to a small piping bag.

Turn half of the macarons upside down and pipe filling over the surface, leaving a small border around the edges. Place the remaining macarons on top of the piped ones, forming whole macarons.

If desired, dust the macarons with confectioners' sugar and additional lime zest before serving.

French macarons are known for being tricky to master, often ending up hollow, cracked, or misshapen, even sometimes for experienced bakers. When making them at home, keep a few key tips in mind. 

Start with room temperature egg whites — they whip up more quickly and with better volume than their straight-from-the-fridge counterparts. (That said, you may want to separate the egg whites from yolks while the eggs are cold, then leave the whites out to come to room temp.) Sift the almond flour and confectioners' sugar to eliminate lumps. You can also do this by pulsing them quickly in a food processor. For the meringue, watch your peaks along the way. Whip the egg whites until frothy and add the sugar slowly to help it dissolve evenly. Whip to medium peaks, where the peaks slightly curve at the tips when the whisk is lifted out of the bowl. Add food coloring at this stage to prevent overwhipping by the time the color is uniform.

The most common mistakes are made when folding the batter. Fold gently using a rubber spatula, and fold only until the batter is lava-like and falls back into itself when lifted. Err on the side of underfolding. While underfolded macarons will be thicker (like little hamburgers), they won't spread excessively and become flat. Pipe your macarons without swirling — hold the bag in one spot and apply pressure to form small rounds. Finally, bake the macarons only until firm and able to release from the pan, but avoid overbaking to maintain that signature delicate, chewy texture.

There are a few key differences between standard (Persian) limes and key limes. Key limes are smaller, often more yellow when ripe, and contain more seeds but less juice than Persian limes. The main distinction, however, lies in the flavor. Key limes offer an intense and tangy, but sweet and floral flavor, while Persian limes are more acidic. 

Although you can substitute one for the other, classic recipes like key lime pie or these key lime macarons benefit from the unique flavor of key lime juice. In a pinch, a mix of lemon and lime juice can mimic that flavor. While Persian limes are available year-round, you'll find key limes mainly from June to September, although the juice can often be found in bottled forms throughout the year. For the most nuanced flavor, using true key lime juice makes all the difference — but if regular limes are all you have access to, don't sweat it. Your macarons will still be delightfully tangy, bright, and citrusy.