In a medium, heavy-bottomed saucepan, whisk together the granulated sugar, salt, and cornstarch until no lumps remain.

Add 1 cup heavy whipping cream, the whole milk, and the egg yolks. Whisk vigorously until smooth and fully combined.

Place the saucepan over medium heat. Cook, whisking constantly and scraping the bottom and corners of the pan, for about 5 to 7 minutes, until the mixture thickens to a pudding-like consistency.

Remove the saucepan from the heat and pour the hot custard through a fine-mesh strainer set over a clean bowl. Press it through with a spatula and discard any lumps or cooked egg.

Add the butter pieces one at a time, stirring until each piece is melted and incorporated. Stir in the vanilla extract.

Place plastic wrap directly onto the surface of the warm custard. Refrigerate for at least 3 to 4 hours, or preferably overnight, until completely chilled and firm.

Use the large end of a piping tip or a small, sharp knife to cut a small hole into one side of each Hawaiian roll without piercing through the other side.

Gently press down the bread inside each roll with your finger or the back of a small spoon to create a cavity.

Spoon the chilled custard into a large piping bag fitted with a long, thin piping tip. Insert the tip into each roll and pipe in the custard until full.

Place the semi-sweet chocolate chips and ⅓ cup heavy whipping cream in a small microwave-safe bowl.

Microwave in 20-second intervals on high power, stirring vigorously after each interval, until the chocolate is fully melted and the glaze is smooth and glossy.

Dip the top of each filled roll into the warm chocolate glaze and allow the excess to drip off.

Place the glazed rolls on a wire rack or serving plate and let them sit at room temperature for 5 to 10 minutes, until the glaze sets.

Serve slightly warm or at room temperature.