In a small bowl, warm the milk until lukewarm, then sprinkle in the yeast and let it sit for about 5 minutes until foamy.

In a separate mixing bowl, whisk together the beaten egg and softened butter, then pour in the yeast mixture and stir until well combined.

In another bowl, whisk together the flour, sugar, and salt. Gradually add this dry mixture to the wet ingredients, stirring until a dough forms.

Transfer the dough to a floured surface and knead for about 5-7 minutes until smooth and elastic.

Place the kneaded dough in a greased bowl, cover with a towel, and allow it to rise in a warm area for about 1 hour until doubled in size.

While the dough rises, mix the pistachio butter, brown sugar, and ground cinnamon in a bowl until well combined.

Once the dough has risen, roll it into a rectangle about ½ inch thick, spread the pistachio filling evenly, then roll tightly and slice into 4-6 pieces.

Arrange the sliced rolls in a greased baking dish, cover loosely, and allow to rise for another 30-45 minutes.

Preheat your oven to 350°F (175°C) and bake the rolls for 23-30 minutes until golden brown.

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

Allow the rolls to cool slightly before icing them generously and adding chopped pistachios on top.