Make the dough starter: In the bowl of a stand mixer fitted with the paddle attachment, combine 2 (0.25-ounce) packages active dry yeast and 3 tablespoons granulated sugar. Add 1½ cups warm milk (100° to 110°F). Let sit until foamy, about 10 minutes.

Mix the dough: Add 1 large egg and 6 tablespoons softened unsalted butter to the foamy yeast mixture. Beat at medium speed until creamy, about 1 minute.

Add flour and salt: Beat in one-third of the 5 cups all-purpose flour (flour is divided) until combined. Add 1½ teaspoons salt and the remaining 3 tablespoons granulated sugar; beat to combine. Gradually beat in the remaining two-thirds of the flour until incorporated.

Knead the dough: Switch to the dough hook attachment and knead at low speed until the dough is smooth and elastic, about 4 minutes.

Chill the dough: Lightly spray a large bowl with cooking spray. Place the dough in the bowl and turn it once to grease the top. Cover tightly with plastic wrap and refrigerate overnight.

Make the pastry cream: In a medium heavy-bottomed saucepan, bring 2 cups whole milk and 5 tablespoons granulated sugar to a boil over medium-high heat. Remove from heat.

Prepare the egg mixture: In a medium bowl, whisk together 3 large egg yolks, 1 large whole egg, 3 tablespoons cornstarch, 1/4 teaspoon salt, and the remaining 1/4 cup granulated sugar until smooth.

Temper and cook the pastry cream: Whisk a small amount of the hot milk into the egg mixture to temper it, then continue adding the hot milk in small additions, whisking constantly, until you have added enough hot milk to warm and thin the egg mixture (about an equal volume to the egg mixture). Return the tempered egg-milk mixture to the saucepan and cook over medium-high heat, whisking constantly, until it thickens and begins to bubble (reduce heat to medium if it starts to stick).

Finish and chill the pastry cream: Remove from heat and whisk in 1/4 cup (58 g) unsalted butter and 1 teaspoon vanilla extract. Transfer the pastry cream to a heatproof bowl set in a larger bowl filled with crushed ice and whisk occasionally until cool. Press plastic wrap directly onto the surface of the pastry cream and refrigerate. (Can be refrigerated up to 3 days.)

Make the cinnamon-sugar filling: In a small bowl, whisk together 1 cup granulated sugar, 2 tablespoons cinnamon, and 1/2 teaspoon salt until combined.

Make the glaze: In a medium bowl, whisk together 2½ cups confectioners’ sugar and 3 to 4 tablespoons whole milk until you reach the desired pouring consistency. Set aside.

Prepare for assembly: Line a rimmed baking sheet with parchment paper. Lightly flour a clean work surface.

Roll the dough: On the lightly floured surface, roll the chilled dough into an 18 x 13-inch rectangle.

Fill the dough: Spread a thin, even layer of the chilled pastry cream over the dough, leaving a 1-inch border on all sides. Sprinkle the cinnamon-sugar mixture evenly over the pastry cream.

Roll and seal: Starting at one long side, roll the dough up tightly into a log (jelly-roll style). Brush the long seam with the 1 large egg (lightly beaten) and press to seal. Trim the uneven ends and discard or reserve.

Cut the rolls: Using a serrated knife, cut the log into 2-inch sections and place the cut rolls, cut-side up, on the prepared baking sheet.

Proof the rolls: Cover the rolls loosely with a thin dish towel and let them stand in a warm, draft-free place (about 85°F) until doubled in size, about 1 hour.

Bake: Preheat the oven to 350°F. Bake the rolls for 25 minutes, rotating the pan halfway through baking for even browning.

Finish and serve: Remove the rolls from the oven and let them cool slightly while covered with a thin dish towel. Spoon the prepared glaze over the warm rolls and serve slightly warm.