Panera Chocolate Croissant Recipe

Name: Panera Chocolate Croissant Recipe
Ingredients: 1 tablespoon active dry or instant yeast; 1/4 cup superfine sugar; 1 and 1/2 cups chilled whole milk; 1/4 teaspoon ground cinnamon; 1/4 cup unsalted butter (softened to room temperature); 4 cups all-purpose flour (plus extra for rolling and shaping); 2 teaspoons sea salt; 1 bar dark chocolate (roughly chopped (semi-sweet or bittersweet)); 2 tablespoons all-purpose flour; 1 tablespoon brown sugar; 1 and 1/2 cups unsalted butter (softened); 2 tablespoons whole milk; 1 large egg; Powdered sugar for a light dusting at the end