Mix together the yeast and warmed milk in a small bowl, setting aside for a few minutes.
Cream the butter and sugar together. Then beat in the eggs and add the yeast and milk mixture. Mix in the salt and gradually add in the flour until a soft and slightly sticky dough forms.
Switch your mixer to a dough hook or take the dough out of the bowl and knead the dough. This works best if you lightly oil your hands and the work surface first.
When an elastic ball of dough has formed, transfer it to a greased bowl and cover with a towel, and place it in a warm spot to rise for about 1 hour or until doubled in size.
While the dough is sitting, make the cinnamon filling by combining the ingredients in a small bowl. Preheat the oven to 350 degrees.
After the dough has sat, punch it down and knead for about 5 minutes. Roll it into a rectangle and spread the filling on half of it, then fold it over. Cut the rectangle into three strips, braiding them together and then shaping the braid into a large ring, pressing the ends together. Carefully insert your trinket into the dough ring.
Transfer the ring to a cookie sheet and bake for 35-40 minutes or until golden brown.
After the cake has cooled, you can make a simple icing with powdered sugar, milk, and vanilla and sprinkle colored sugar on the ring, if desired.