Warm milk to 95°F and whisk with sugar and yeast; let foam 5-10 minutes.
Beat in softened butter, add eggs one at a time, then salt.
Gradually add flour and beat on medium to medium-high until soft elastic dough, about 6 minutes.
Knead dough by mixer or hand 5 more minutes, adding flour if sticky but keep dough soft.
Test dough by finger poke and windowpane test.
Shape dough into ball, place in greased bowl, cover and rise 1-2 hours until doubled.
Line baking sheet with parchment, flour lightly and pat dough into 10×20 inch rectangle.
Spread softened butter over dough.
Mix cinnamon and sugar, sprinkle evenly over butter.
Roll dough from long side into a 20-inch log.
Cut into 20 pieces about 1 inch wide, slicing three-quarters through.
Arrange rolls overlapping in a circle to form wreath; place ramekin in center.
Cover loosely, place large baking sheet underneath, let rise until puffy 45-60 minutes.
Preheat oven to 350°F.
Bake wreath about 25 minutes until golden brown.
Cool 10 minutes before icing.
Whisk confectioners’ sugar, vanilla, and milk for icing and drizzle over warm wreath.