Line a cookie sheet with a silicone mat. Optionally, use parchment paper.

In a food processor add the powdered sugar and almond flour and pulse until fully combined and rid of lumps. Sift the dry ingredients into a large bowl.

Whisk the poppy seeds into the dry ingredients.

Prepare the french meringue: Beat the egg whites on low speed until frothy. Slowly add the sugar and beat until stiff peaks form.

Gently fold the french meringue into the dry ingredients until fully combined.

Transfer the batter to a piping bag fitted with a piping tip and pipe 1-inch disks onto the prepared cookie sheet.

Tap the cookie sheet onto the counter 3 or 4 times to bring any air bubbles to the surface. Use a toothpick to pop any remaining air bubbles.

Let the macarons rest for an hour.

Preheat the oven to 280 degrees (F).

Bake macarons for a total of 15 minutes, rotating the cookie sheet as instructed.

Remove from the oven and allow to cool completely. Match each shell to another of the same size.

In a medium heat-proof bowl whisk together the sugar, lemon juice, egg, and egg yolk.

Place the bowl over a small saucepan of simmering water and add the butter.

Let the mixture cook over low heat for about 15 minutes, whisking occasionally.

The curd is ready when a thermometer reads 180 degrees (F) or when it has the consistency of mayonnaise.

Remove the curd from the heat and cover with plastic wrap. Refrigerate until fully cooled.

Whip the heavy cream to stiff peaks using a hand mixer.

When cooled, gently fold the curd into the whipped cream until fully combined.

Transfer the whipped lemon curd to a piping bag and fill the macaron shells.