In a small saucepan, heat milk over medium heat until scalding. (An instant-read thermometer should register 180°F/82°C.) Let cool until an instant-read thermometer registers 110°F (43°C) to 115°F (46°C).
In a small bowl, whisk together warm milk, 1 teaspoon (4 grams) granulated sugar, and yeast. Let stand until foamy, 5 to 10 minutes.
In the bowl of a stand mixer, whisk together 2 cups (254 grams) flour, salt, and remaining 4 tablespoons plus 2 teaspoons (56 grams) granulated sugar by hand. Add warm yeast mixture, Tangzhong, and egg; using the paddle attachment, beat at low speed until well combined. With mixer on low speed, gradually add 1¾ cups (222 grams) flour, beating just until a shaggy dough comes together and stopping to scrape bottom and sides of bowl.
Switch to the dough hook attachment. Beat at low speed until dough is tacky, elastic, and slightly smooth, about 8 minutes; add up to remaining 1⁄4 cup (32 grams) flour, 1 tablespoon (8 grams) at a time, if dough is too sticky. Add 5 tablespoons (70 grams) butter, 1 tablespoon (14 grams) at a time, beating until combined after each addition (about 5 minutes total). Scrape bottom and sides of bowl and dough hook. Beat until dough is completely smooth and passes the windowpane test, about 12 minutes. (See Note.) Turn out dough onto a clean surface, and shape into a smooth round.
Lightly oil a large bowl. Place dough in bowl, turning to grease top. Cover and let rise in a warm, draft-free place (75°F/24°C) until doubled in size, 45 minutes to 1 hour.
In another small bowl, stir together brown sugar, cinnamon, and remaining 1⁄2 cup (113 grams) butter.
Spray a 13×9-inch baking pan with baking spray with flour. Line pan with parchment paper, letting excess extend over long sides of pan.
Turn out dough onto a lightly floured surface, and roll dough into a 18×12-inch rectangle with one long side closest to you. Spread brown sugar mixture on dough in an even layer, leaving a 1⁄4-inch border on long side closest to you. Starting with long side opposite border, roll dough up into a log, pinching seams to seal. Trim ends, and cut log into 12 (1½-inch-thick) slices. Place slices, cut side down, in prepared pan. Cover with plastic wrap, and let rise in a warm, draft-free place (75°F/24°C) until puffed, 45 minutes to 1 hour.
Preheat oven to 350°F (180°C).
Pour cream evenly all over rolls.
Bake until golden brown and an instant-read thermometer inserted in center registers at least 190°F (88°C), 30 to 35 minutes. Let cool in pan for 10 to 15 minutes. Using excess parchment as handles, remove from pan. Spread Cream Cheese Icing on rolls, and serve warm or at room temperature. Refrigerate in an airtight container for up to 3 days.