Step 1

In a small saucepan over medium heat, combine the water, milk and flour. Whisk together and cook, stirring, until mixture thickens. This will take 3 to 4 minutes. The mixture will be the consistency of thick pudding. Remove from heat; set aside.

Step 2

In the bowl of an electric mixer fitted with the dough hook, combine the flour, salt, instant yeast, and dry milk. Add the warm milk, eggs, melted butter and reserved tangzhong paste.

Step 3

Mix the dough on medium speed until combined. Dough will be dry and form a ball. Cover bowl with a clean towel and let rest 20 minutes.

Step 4

After 20 minutes mix dough on medium-high speed for 1 to 2 minutes until a smooth dough forms. Scrape down from dough hook as needed to allow dough to mix evenly. Remove dough hook and use a rubber scraper to bring dough together into a ball. Spray the inside of the bowl with cooking spray.

Step 5

Cover bowl and transfer to a warm place to proof. Let rise until almost doubled in bulk and finger imprint remains and doesn't bounce back when touched, 60 to 90 minutes, depending on the warmth and environment.

Step 6

Turn dough out onto a floured work surface. Gently press into a small rectangle shape, then roll into a 12-by-19-inch rectangle.

Step 7

Spread filling butter over the entire surface. Sprinkle evenly with brown sugar. Sprinkle cinnamon evenly over the top.

Step 8

Starting with a long edge, roll dough around filling into a spiral log. Pinch open edge so it stays together.

Step 9

Use thread or a knife to cut log into 15 rolls. (Alternatively you can cut it into 12 pieces for large rolls.). Place rolls, cut side up, in a buttered jelly roll pan (10-by-15-inch pan).

Step 10

Cover pan and let rolls rise until almost double in bulk, 45 to 60 minutes depending on the warmth and environment.

Step 11

When rolls have almost proofed completely, heat oven to 350ºF with rack in the center.

Step 12

Bake rolls until just turning golden, 22 to 26 minutes.

Step 13

In a mixing bowl beat the butter until smooth. Add the confectioners' sugar a little at a time, mixing, until frosting comes together. Add vanilla. Scrape down sides of bowl and mix thoroughly.

Step 14

Spread icing on warm, not hot, rolls.