Preheat the oven to 325°F and line two baking sheets with parchment paper or silicone mats.
Place a heatproof bowl over a small pot of simmering water. Add the egg whites and granulated sugar to the bowl and whisk until the sugar fully dissolves (about 3 minutes).
Transfer the egg whites to the bowl of a stand mixer fitted with the whisk attachment.
Beat the egg whites on medium-high speed until they form stiff peaks (about 2 minutes).
Add gel food coloring (if using). Sift the powdered sugar and almond flour into the egg whites using a fine mesh sieve. Fold in gently by making a “J” shape with your spatula.
Once all the dry ingredients have been incorporated, smush the batter against the sides of the bowl and fold it back together. Repeat a few times. Test the meringue. If you can draw a figure 8 without the stream breaking, the meringue is ready. If the stream breaks, smush and fold a few more times before retesting.
When the mixture flows smoothly, transfer it to a piping bag fitted with a small round tip (I like a Wilton #10). Pipe 1.5-inch circles about 2” apart onto the baking sheets. Hold the tray off the counter and drop it straight down, repeat 4 to 5 times until it looks like any large air bubbles have popped.
Set the macarons aside to rest for 30 minutes or until you can touch them lightly and they don’t stick to your finger.
Bake the macarons one tray at a time for 14 minutes, turning the pan half-way through to allow for even baking.
Transfer pans to a wire rack. Allow the macarons to cool fully.
To Make the Lemon Buttercream Filling
In a medium mixing bowl, add the butter and beat on medium speed using a hand or stand mixer until it is light (about 2 to 3 minutes).
Gradually add in the powdered sugar while the mixer is on low speed.
Add the lemon juice and lemon zest (and food coloring, if using). Turn the mixer to high speed and beat until the icing is light and fluffy (about 3 to 4 minutes).
Transfer the lemon buttercream to a piping bag fitted with your choice of tip.
To Assemble and Age
Place the macarons into similar sized pairs and pipe a ring of the lemon buttercream around the edge of one shell of each pair. Fill the center with strawberry jam and place the second macaron shell on top pressing them together gently. Repeat with the remaining macarons.
Transfer the filled macarons to an airtight container and place them in the fridge to age overnight.
Before serving, bring them to room temperature.
Store in an airtight container in the fridge for up to 3 days.
Notes
Notes
I added ¼ teaspoon rose pink and ¼ teaspoon of intense red gel food coloring to the macaron shell and ¼ teaspoon lemon yellow gel food coloring to the filling. Make sure to use gel food coloring, not liquid!