01 - Line two baking sheets with parchment paper or silicone mats. Fit a pastry bag with a 0.5-inch round tip.
02 - Sift almond flour and powdered sugar together into a bowl. Set aside.
03 - In a clean, dry bowl, whisk egg whites and cream of tartar until soft peaks form. Gradually add granulated sugar while whisking until stiff, glossy peaks form.
04 - Gently fold almond flour mixture into meringue in three additions. Tint one-third of batter yellow for yolk effect if desired. Mix until batter flows in thick ribbons (macaronage stage).
05 - Transfer batter to pastry bag. Pipe 32 rounds (1.5 inches diameter) onto prepared sheets. Firmly tap trays to release air bubbles.
06 - Let shells rest at room temperature 30-60 minutes until surfaces are dry. Preheat oven to 300°F. Bake 13-15 minutes, rotating pans halfway. Shells are done when they lift easily from the mat. Cool completely.
07 - Heat heavy cream until just simmering. Pour over milk chocolate and let sit 2 minutes. Stir until smooth. Add golden syrup and butter, mixing until glossy.
08 - Separate one-quarter of filling and tint with yellow gel for yolk centers. Chill both fillings until thickened to pipeable consistency.
09 - Pipe a ring of chocolate filling on one shell. Place a dollop of yellow filling in center for yolk effect. Sandwich with another shell. Repeat with remaining components.
10 - Store assembled macarons in airtight container overnight for flavors to mature. Refrigerate up to 5 days.