In the bowl of a stand mixer with a dough hook attachment, combine yeast and water. Set aside to bloom while you prepare the remaining ingredients.

In a medium saucepan over medium-low heat, add milk, water, and flour. Whisk together well, stirring constantly (but not vigorously). Once it starts to thicken, remove from heat and continue to stir until a thick paste forms. The mixture can take a while to thicken, but when it does, it happens quickly (about 2 minutes). Pour the mixture into a small bowl and set it aside to cool slightly.

To the yeast mixture, add flour, milk, sugar, salt, 1 egg, and the tangzhong mixture. Mix on low speed until the dough starts to come together (about 5 minutes). If the dough is too wet, add flour (1 tablespoon at a time). If it is too dry, add a little extra milk.

With the mixer still on low, add a tablespoon of butter. Mix until fully incorporated. Repeat with the remaining butter (1 tablespoon at a time).

Form the dough into a ball and place in a greased bowl. Cover with plastic wrap and allow to rise in a warm location for 1 hour (or until doubled).

Spray a 9-inch springform pan with nonstick cooking spray.

When you are ready, punch the dough, turn it out onto a floured surface, and divide the dough into 8 equal-sized pieces (about 3 ounces each).

Working one at a time, push down slightly (but firmly and evenly) on the dough sections and roll the ball under your palm in a circular motion. Use the cupped sides of your hands to keep the dough centered in your palm. You may have to work the dough for a while, but eventually, it will come together and most of the lines and folds should have incorporated into the dough, forming a smooth dough ball.

Add the rolls to the prepared pan, spaced apart.

Cover and allow to rise again until doubled (about 30-45 minutes).

Preheat oven to 350°F.

In a small bowl, add remaining egg and water and whisk vigorously until combined and smooth.

Use a pastry brush to brush the tops of the rolls with the egg wash.

Bake 20-25 minutes, or until the tops are golden brown. (The internal temperature of the baked rolls should be 190°F.) Enjoy!