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 for later use.
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. Optionally tint one-third of batter yellow for yolk effect. Mix until batter flows in thick ribbons (proper macaronage consistency).
05 - Transfer batter to prepared pastry bag. Pipe 32 rounds approximately 1.5 inches in diameter onto baking sheets. Firmly tap trays to release air bubbles.
06 - Let piped shells rest at room temperature for 30 to 60 minutes until surfaces are completely dry to touch.
07 - Preheat oven to 300°F. Bake for 13 to 15 minutes, rotating pans halfway through. Shells are done when they easily lift from the mat. Cool completely.
08 - Heat heavy cream until just simmering. Pour over milk chocolate and let stand for 2 minutes. Stir until smooth. Add golden syrup and butter, mixing until glossy.
09 - Reserve one-quarter of filling and tint with yellow gel coloring for egg yolk effect. Chill both fillings until thickened to piping consistency.
10 - Pipe a ring of chocolate filling onto one shell. Place a dollop of yellow filling in center for yolk. Sandwich with another shell. Repeat with remaining ingredients.