In a stand mixer, combine 3 cups of all-purpose flour, 2 tablespoons of granulated sugar, 1 teaspoon of salt, and 2 teaspoons of instant yeast. Gradually add 1 cup of cold whole milk and mix on low speed for about 5 minutes until the dough is soft yet slightly tacky. Wrap the dough in plastic and refrigerate for 30 minutes to relax the gluten.

Blend 1 cup of cold unsalted butter with 2 tablespoons of flour until smooth. Shape into a rectangle about 1/2 inch thick, wrap in parchment paper, and refrigerate for 30 minutes.

Roll the chilled dough into a rectangle approximately 12 x 18 inches. Place the butter rectangle in the center, fold edges to encase it, seal edges tightly, and roll into a 12 x 24-inch rectangle. Fold into thirds like a letter, wrap, and refrigerate for 30 minutes. Repeat this folding process two more times.

Wrap laminated dough tightly in plastic wrap and refrigerate for at least 4 hours or overnight.

Roll the dough into a large rectangle about 12 x 24 inches. Cut into triangles, placing a piece of chocolate baton at the base of each triangle, then roll from the base to the tip. Position shaped croissants on a parchment-lined baking sheet.

Allow rolled croissants to proof at room temperature for about 1 to 1.5 hours until doubled in size. Cover with a clean kitchen towel to prevent drying.

Preheat your oven to 400°F (204°C). Whisk together 1 egg with a splash of milk for the egg wash. Apply the egg wash across the surface of each croissant.

Bake croissants for 20 minutes, rotating halfway through until they are deep golden and puffed.