Start by dissolving the active dry yeast in warm milk (110°F) with a teaspoon of sugar. Allow it to sit for 5-10 minutes until frothy. This step ensures the yeast is alive and ready to work its magic.

Mix together the sugar, softened butter, eggs, vanilla extract, and salt in a mixing bowl. Gradually add in the flour, alternating with the activated yeast mixture. Use a stand mixer with a dough hook attachment to knead the dough for 5 minutes, or knead by hand until it becomes elastic and smooth. Cover the dough with a towel and set it aside to rise in a warm place for 45 minutes.

Punch down the risen dough and roll it out into a large rectangle (about 14x18 inches) on a floured surface. Brush the surface with melted butter, then sprinkle evenly with the filling mixture (brown sugar and cinnamon).

Roll the dough into a log starting from the longer side, then shape it into a circular ring. Pinch the edges to seal the seam, and transfer the ring onto a prepared baking sheet lined with parchment paper. Allow it to rise again for another 45 minutes.

Preheat the oven to 350°F (175°C). Bake the cake for 25-30 minutes, or until golden brown and cooked through. Transfer it to a wire rack to cool completely.

Once the cake has cooled, whisk together the glaze ingredients (powdered sugar, milk, and vanilla) and drizzle over the top. Finish by decorating with purple, green, and gold sprinkles. For added tradition, hide a small plastic baby or trinket under the cake (make sure to inform your guests before serving).