Prepare the Dough: In a stand mixer, combine flour, sugar, salt, and yeast. Gradually mix in cold milk until soft dough forms. Knead for about 5 minutes until smooth.

Make the Butter Layer: Combine softened butter and a bit of flour until smooth. Shape into a rectangle, wrap in plastic, and chill for at least 30 minutes.

Encase the Butter: Roll out the dough to a large rectangle, place chilled butter layer in the center, and fold edges over to seal tightly.

Roll and Fold: Roll into a larger rectangle, fold into thirds like a letter, wrap in plastic, and refrigerate for another 30 minutes.

Perform Additional Turns: Repeat rolling and folding process two more times, chilling between each turn.

Shape the Croissants: Roll out to about ¼ inch thick, cut into triangles, place chocolate on base, and roll into crescent shape.

Proof the Croissants: Arrange shaped croissants on a baking sheet and let proof until doubled. Refrigerate for best results.

Preheat the Oven: Preheat oven to 400°F while croissants proof. Prepare egg wash with egg and milk.

Bake the Croissants: Bake for 20 minutes, rotating halfway through for even browning.

Cool and Serve: Transfer to a wire rack to cool slightly. Dust with confectioners’ sugar and serve warm.