Combine 4 cups of all-purpose flour, 1/4 cup granulated sugar, 2 1/4 teaspoons instant dry yeast, and 1 teaspoon salt in a large mixing bowl. Pour in 1 cup of warm milk, 1/4 cup melted unsalted butter, and 1 beaten egg. Mix until a dough forms, then knead for 5-7 minutes until smooth and elastic.

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

Prepare the filling by mixing 1 cup finely chopped dark chocolate, 2 tablespoons ground cinnamon, and 1/4 cup granulated sugar in a small bowl.

Punch down the risen dough and roll it out into a 12x18-inch rectangle.

Spread the chocolate filling evenly over the rolled dough, then roll tightly from the long side and slice into 12 even sections.

Arrange the rolls in a greased 9x13-inch baking dish, cover with a towel, and let them rise for an additional 30 minutes.

Preheat the oven to 350°F (175°C). Bake for 25 minutes until golden brown.

Let the rolls cool for about 10 minutes, then prepare the glaze by mixing 1 cup powdered sugar with 2-3 tablespoons melted chocolate and drizzle over the rolls.