Warm 1/2 cup of milk until lukewarm, sprinkle in yeast, and let sit for 5 minutes until foamy.

In a mixing bowl, combine egg and softened butter, then add flour, sugar, and salt; stir until a sticky dough forms.

Knead gently on a floured surface for 5 minutes until smooth.

Transfer dough to an oiled bowl, cover with a towel, and let rise in a warm spot for about 1 hour.

Prepare filling by mixing pistachio butter, brown sugar, and cinnamon until smooth.

Roll risen dough into a rectangle, spread filling evenly, and roll tightly into a log.

Cut log into 4 to 6 pieces and place in a greased baking dish, letting rise for 30 to 45 minutes.

Preheat oven to 350°F and bake rolls for 23 to 30 minutes until golden brown.

Prepare icing by whisking cream cheese, powdered sugar, vanilla extract, and heavy cream until smooth.

Once rolls cool slightly, spread icing generously and serve.