Warm the milk, butter, and granulated sugar in a saucepan until the butter melts. Cool the mixture to lukewarm, approximately 105-110°F, then stir in the yeast and let it stand for 5-10 minutes until foamy.

Beat in the eggs and salt. Add the flour gradually, mixing until a soft, slightly tacky dough forms.

Knead the dough by hand for 6-8 minutes or with a dough hook for 5-7 minutes, adding flour sparingly. Place it in a greased bowl, cover, and let it rise in a warm, draft-free place for 60-90 minutes, until doubled.

Mix the softened butter, brown sugar, and cinnamon to make the filling. Stir in the chopped pecans if using.

Roll the dough into a rectangle approximately 10 by 30 inches. Spread the filling evenly over the dough, leaving a small edge clear, then roll it up from the long side into a rope.

Join the rope's ends and pinch the seam closed to form an oval or ring. Transfer it to a parchment-lined baking sheet, cover, and let it rise for another 30-45 minutes.

Bake at 350°F for approximately 25-35 minutes, until golden brown and about 190°F internally. If the top browns too quickly, loosely cover it with foil.

Cool the cake completely. Whisk the powdered sugar, milk or cream, and vanilla into a thick but pourable glaze, then spread or drizzle it over the cake.

Add alternating purple, green, and gold or yellow sugar while the glaze is still slightly wet. Insert the plastic baby from the underside only after the cake has cooled, and never bake the plastic figure inside the cake.