In a stand mixer bowl, combine warm milk, yeast, and granulated sugar. Let sit 5 minutes until foamy. Add eggs, salt, and flour, mix to a shaggy dough, then knead with dough hook on medium-low 8 to 10 minutes. Add soft butter a little at a time, kneading after each, then knead 3 to 4 more minutes until smooth and elastic.

Place dough in a greased bowl, cover, and let rise in a warm spot until doubled, about 1 to 1 1/2 hours.

Punch down dough, roll out on a floured surface to a 12x18 inch rectangle. Spread 1/2 cup soft butter over dough, then sprinkle with brown sugar and cinnamon mixture. Roll up tightly from the long side.

Cut into 12 equal pieces and place in a buttered 9x13 inch pan. Cover and let rise until puffy and touching, 45 minutes to 1 hour. Preheat oven to 350°F (175°C) near the end.

Bake on the middle rack for 22 to 26 minutes, until deep golden. Cool in the pan on a rack for 10 minutes.

Beat cream cheese and 1/4 cup butter until smooth, then mix in powdered sugar, vanilla, and salt. Thin with milk to a spreadable consistency. Frost the warm rolls and serve.