Stir together warm milk, yeast, and 1 tablespoon sugar in large bowl. Let stand 5-10 minutes or until foamy. Add 1/2 cup butter, remaining 3 tablespoons sugar, egg yolks, 1 teaspoon vanilla and salt. Mix with electric mixer using dough hook on medium speed until combined. Gradually add 4-1/2 cups flour, 1 cup at a time, and mix on medium speed until a smooth, elastic dough forms, about 5 minutes.

Spray large bowl with vegetable pan spray. Form dough into a ball, place into bowl and cover with plastic wrap. Let stand in a warm place 45 minutes or until doubled in size.

For filling, stir together 1/2 cup butter, 1/3 cup sugar, 2 tablespoons flour and cinnamon in medium bowl until well-combined.

Prepare a large cookie pan with parchment paper.

Punch dough down and roll out to a 10 in. x 28 in. rectangle on floured surface. Spread filling onto dough and roll up from long end, as for a cinnamon roll. Cut log in half lengthwise, twist pieces together, and form into a ring on prepared pan, tucking ends under.

Loosely cover with plastic wrap and let rise 25-30 minutes.

Meanwhile, preheat oven to 350°F. Remove plastic wrap and bake 25-29 minutes or until golden brown. Cool completely on cooling grid.

For glaze, stir milk and 1/2 teaspoon vanilla into confectioners’ sugar until a thick glaze forms. Drizzle over cooled king cake and sprinkle with sugars.