Partially melt ½ cup salted butter in the microwave for 15 seconds, then use a pastry brush to stir and brush the butter all over the surface of the dough. Yes, we are partially melting already room temperature butter because this allows us to do a quick partial melt and stir the butter into a creamy paste-like consistency for brushing. You don't want to use all melted butter for this step because it's too thin and won't hold the filling in as well.
In a medium bowl, stir together 1 cup dark brown sugar, 2 tablespoons corn starch, and 2 tablespoons ground cinnamon with a fork until mixed.
Sprinkle the cinnamon sugar mixture over the butter, and leave a ½ to 1-inch border at one of the shorter ends. Then use a rolling pin to roll over and press the sugar into the dough.
Use a pizza or pastry cutter to cut the dough into 12 strips about 1⅓-inch wide with, the cuts starting from the shorter (16-inch) side of the dough.
Roll up each strip of dough to create a pinwheel, starting with the fully sugared end, making sure it's fairly tight, then securing with the exposed buttered end without sugar on it. You can brush more butter onto the outside of the roll if needed to secure the end.
Place the rolls on the parchment-lined baking pan with a little space between.
Pour ¾ cup heavy cream over the top of the cinnamon rolls right before covering for their second rise. (You can skip this step if desired and carry on with the recipe with no additional changes).
Cover the rolls with plastic wrap and transfer the covered rolls to the refrigerator immediately after placing them on the pan for a second slow rise for 8 to 12 hours. The rolls should be touching and crowding each other and be fairly puffy once proofed.
Preheat the oven to 350ºF.
Bake the rolls on the lowest rack of the oven for 24 to 28 minutes or until golden brown. When done, the center of the rolls should read 190°F on an instant-read thermometer. Transfer the pan to a wire rack to cool.