01 - Line two baking sheets with parchment paper or silicone mats. Fit a pastry bag with a 1/2-inch round tip and set aside.
02 - Sift almond flour and powdered sugar together into a bowl until thoroughly combined. Set the mixture aside.
03 - In a clean, dry bowl, whisk egg whites and cream of tartar until soft peaks form. Gradually add granulated sugar while whisking, continuing until stiff glossy peaks form.
04 - Gently fold almond flour mixture into meringue in three additions. Optionally tint one-third of batter with yellow coloring. Mix until batter flows in thick ribbons and drips slowly from spatula.
05 - Transfer batter to prepared pastry bag. Pipe 32 rounds approximately 1.5 inches in diameter onto baking sheets. Firmly tap trays against counter to release air bubbles.
06 - Let shells rest at room temperature for 30 to 60 minutes until surfaces form dry skin. Preheat oven to 300°F. Bake for 13 to 15 minutes, rotating pans halfway. Shells are done when they easily release from mat. Cool completely.
07 - Heat heavy cream until just simmering. Pour over chopped milk chocolate and let stand 2 minutes. Stir until smooth. Add golden syrup and butter, mixing until glossy. Chill until thickened.
08 - Tint one-quarter of filling with yellow gel coloring for 'yolk' effect. Pipe ring of chocolate filling on shell, add dollop of yellow filling in center, and sandwich with second shell. Repeat with remaining shells.
09 - Place assembled macarons in airtight container and refrigerate overnight to mature flavors. Store refrigerated up to 5 days.