Bring the eggnog to room temperature. While it is sitting out, put all the butter in a medium sized saucepan over med-high heat. Bring it to a boil and let it cook, stirring it constantly until it begins to brown and get a nutty aroma.
Immediately remove the butter from the heat and separate (1/2 cup for the rolls and 1/3 cup for the filling).
Barely heat the water up until it is just above room temperature and add the yeast into it. Let it sit for 5 minutes or so until the yeast blooms and becomes fragrant.
In a stand mixer with a dough hook, add 1/2 cup of the browned butter (make sure it has cooled to become just warm, not hot), the yeast and water, and eggnog, Mix together and add eggs one at a time. Slowly add the flour, sugar and salt while the mixer is on low-medium. Let it knead the dough for about 5 minutes in order to get all the gluten working. The dough should become sticky and stretchy.
Cover the dough and let it rise in a warm place for 1 ½ hours.
Prepare the filling by mixing the cinnamon, nutmeg and sugar together.
On a well floured surface, roll the dough into a rectangle roughly 14” x 24”. That doesn’t have to be exact.
Drizzle the 1/3 cup of browned butter all over the rolled dough, leaving about a 1 inch perimeter around the edges without butter.
Evenly sprinkle the sugar mixture all over on top of the butter.
Roll the dough to form a long log and cut the edge off of each side. With a sharp serrated knife, cut out 24 rolls.
Place them into two- 7”x11” greased pans and cover them with plastic.
At this point you can either put them in the fridge overnight or let them rise for another 30 minutes before baking them. *
Preheat the oven to 375°F and bake the cinnamon rolls for 20-25 minutes until they are golden brown on the top.
Remove the cinnamon rolls from the oven and let them cool for about 10 minutes before frosting them.
Stir the powdered sugar and eggnog together to make the frosting. Drizzle the frosting over the top of the cinnamon rolls and serve.
Notes
These cinnamon rolls freeze well. I usually freeze one pan at this point and put the other in the fridge overnight.