Warm the Whole Milk until it is just lukewarm (about 100–110°F / 38–43°C), then stir in a pinch of Granulated Sugar and sprinkle the Active Dry Yeast over the surface; let sit 5–10 minutes until foamy.
In a large mixing bowl whisk together the Eggs, Egg Yolks, the remaining Granulated Sugar, the Orange Zest and a splash of Orange Blossom Water until combined and slightly aerated.
Add the foamy yeast-milk to the egg mixture, then begin incorporating the All-Purpose Flour and a pinch of Fine Salt to form a shaggy dough.
Turn the dough onto a lightly floured surface and knead, gradually working in softened Unsalted Butter a little at a time until fully absorbed; continue kneading until the dough is smooth, elastic and slightly tacky (about 8–12 minutes by hand or 5–7 minutes in a stand mixer).
Place the kneaded dough in a lightly oiled bowl, cover with plastic wrap or a towel, and let it rise in a warm place until doubled in size, about 1–2 hours depending on temperature.
Punch the dough down and divide most of it into a round loaf for the base; reserve smaller pieces to form the traditional decorative strips and a small round 'bone' for the crown.
Shape the base into a smooth round and arrange the strips and small ball on top to resemble bones and a crown, pressing gently so they adhere. Place the shaped loaf on a baking sheet lined with parchment.
Cover the shaped loaf and let it proof until puffy, about 45–60 minutes, while you preheat the oven to 350°F (175°C).
Brush the loaf gently with a beaten egg for a shiny finish, then sprinkle generously with Granulated Sugar.
Bake until the loaf is golden brown and sounds hollow when tapped, about 25–35 minutes; if the top browns too quickly, tent with foil for the last 10 minutes.
Let the Pan de Muerto cool slightly on a rack before slicing so the crumb sets; serve warm or at room temperature, enjoying the buttery, citrusy aroma and tender texture.
