Prepare Your Baking Sheet: Line a baking sheet with a silicone mat or parchment paper.

Combine Dry Ingredients: Pulse powdered sugar and almond flour in a food processor, sift into a bowl, and whisk in poppy seeds.

Whip the Egg Whites: Beat egg whites until frothy, gradually add granulated sugar until stiff peaks form.

Combine Ingredients: Gently fold meringue into the dry ingredients to create a smooth, glossy batter.

Pipe the Macarons: Transfer batter to a piping bag and pipe 1-inch disks on the baking sheet.

Let Them Rest: Tap baking sheet to release air bubbles and let macarons rest for 1 hour until tops feel dry.

Preheat and Bake: Preheat oven to 280°F and bake macarons for 15 minutes, rotating halfway through.

Cool Down: Let macarons cool on the baking sheet for 10 minutes before transferring to a wire rack.

Make the Lemon Curd Filling: Whisk lemon juice, eggs, and sugar over simmering water until thickened; add butter until smooth.

Fold in Cream: Once cooled, fold in heavy whipping cream until combined.

Assemble the Macarons: Pipe lemon curd filling onto half of the macaron shells and sandwich with the remaining shells.

Chill and Serve: Refrigerate assembled macarons for 30 minutes before serving.