In a large mixing bowl, combine 3 cups of all-purpose flour, 1 large egg, and 1 cup of warm milk, along with ¼ cup of melted butter, ¼ cup of sugar, 1 packet of instant yeast, and a pinch of salt. Mix until a soft dough forms, then knead for about 8-10 minutes until smooth and elastic. Place the dough in a greased bowl, cover it with a cloth, and let it rise in a warm spot for 1-2 hours, until it doubles in size.

After the dough has risen, flour your work surface lightly and turn out the dough. Using a rolling pin, roll it into an 11x16-inch rectangle, about ¼ inch thick. Spread ¼ cup of softened butter evenly over the surface, then sprinkle a mixture of 1 cup of sugar and 2 tablespoons of cinnamon, along with any optional raisins or nuts, over the buttered dough.

Starting from the long edge, tightly roll the dough into a log. Pinch the edges to seal the roll, then use a serrated knife or dental floss to cut the log into 12 equal pieces. Arrange the cut rolls in a greased baking dish, allowing space for them to expand. Cover the dish with a kitchen towel and let the rolls rise for an additional 45-90 minutes until they become puffy.

Preheat your oven to 350°F (175°C). Once the rolls have risen adequately, place them in the oven and bake for 20-25 minutes, or until they are golden brown and the tops are slightly firm to the touch.

While the rolls are baking, prepare the creamy frosting by beating together 4 ounces of softened cream cheese, 1 cup of powdered sugar, and a splash of vanilla extract until smooth.

Once the Best Fluffy Cinnamon Rolls are out of the oven, let them cool for about 10 minutes. Generously spread or drizzle the frosting over the warm rolls, allowing it to melt into the swirls.