Prepare the Tangzhong: In a small saucepan, whisk together the warm water and 2 tablespoons of all-purpose flour over medium heat until thickened and smooth. Let it cool.

Make the Dough: Combine 3 cups of all-purpose flour, 1/3 cup granulated sugar, 2 teaspoons instant yeast, and 3/4 teaspoon fine sea salt. Add heavy cream, milk, egg, and cooled tangzhong. Knead for 11-12 minutes until smooth.

Rest the Dough: Shape the dough into a ball, place in a greased bowl, and cover. Let it rest in a warm place for 30 minutes.

Make the Filling: Cream together 8 tablespoons of unsalted butter, 1/8 cup granulated sugar, and 1/2 teaspoon fine sea salt. Mix in egg, then flour and baking powder. Stir in mini chocolate chips.

Form the Rolls: Roll out dough into a rectangle, spread filling, and cut into strips. Roll tightly and place in a greased baking pan.

Rise: Cover and let rolls rise for about 1 hour or until doubled in size. Preheat oven to 325°F (162°C).

Bake: Bake for 30-40 minutes until golden brown and a thermometer reads 170°F.

Prepare Frosting: Whip together 4 tablespoons butter and 4 ounces cream cheese. Mix in powdered sugar, heavy cream, and vanilla extract.

Frost: Let rolls cool for 15-20 minutes, then frost generously. Serve immediately.