01 - Line two baking sheets with parchment paper or silicone mats. Fit a pastry bag with a 1/2-inch round tip.
02 - Sift almond flour and powdered sugar together into a bowl. Set aside.
03 - In a clean, dry bowl, beat egg whites and cream of tartar until soft peaks form. Gradually incorporate granulated sugar, beating until stiff, glossy peaks form.
04 - Gently fold almond flour mixture into meringue in three additions. For decorative effect, tint one-third of batter with yellow coloring. Mix until batter flows in thick ribbons (macaronage stage).
05 - Transfer batter to pastry bag. Pipe 32 rounds (approximately 1.5 inches diameter) onto prepared baking sheets. Firmly tap trays to release trapped air bubbles.
06 - Let piped shells rest at room temperature for 30 to 60 minutes until surfaces form a dry skin and no longer feel tacky to touch.
07 - Preheat oven to 300°F. Bake for 13 to 15 minutes, rotating pans halfway through baking. Shells are done when they easily detach from baking mat. Cool completely before filling.
08 - Heat heavy cream until just simmering. Pour over chopped milk chocolate and let stand for 2 minutes. Stir until completely smooth. Incorporate golden syrup and butter, mixing until glossy and emulsified.
09 - Reserve one-quarter of chocolate filling and tint with yellow gel food coloring. Refrigerate both fillings until thickened to pipeable consistency.
10 - Pipe a ring of chocolate filling onto one shell. Place a small dollop of yellow filling in center to resemble egg yolk. Gently press another shell on top. Repeat with remaining components.
11 - Place assembled macarons in an airtight container. Refrigerate overnight to allow flavors to develop and shells to soften slightly. Best consumed within 5 days.