In a large mixing bowl, combine the warm milk and yeast. Let sit for 5 minutes until foamy. Add sugar, eggs, melted butter, salt, cinnamon, nutmeg, and 2 ½ cups of flour. Mix until a soft dough forms. Knead by hand or with a dough hook, adding more flour as needed, for about 8–10 minutes until smooth and elastic. Cover and let rise in a greased bowl for 1 to 1.5 hours, or until doubled in size.

Once risen, punch down the dough and turn it out onto a lightly floured surface. Roll it into a large rectangle (about 10x20 inches). Spread the melted butter across the dough, then sprinkle the cinnamon-sugar mixture evenly over it. Roll the dough up tightly from the long side, then form a ring, pinching the ends together. Transfer to a parchment-lined baking sheet.

Cover the dough ring loosely and let it rise for 30–45 minutes until puffy. Preheat your oven to 350°F (175°C). Bake the cake for 25–30 minutes, or until golden brown. Let it cool completely before decorating.

Mix the powdered sugar, vanilla, and milk to form a thick glaze. Drizzle the icing over the cooled cake and immediately sprinkle with purple, green, and gold sugars in alternating sections. If desired, insert a plastic baby into the underside of the cake before serving.