Make the dough: In a large bowl, whisk together the flour, sugar, yeast, and salt.

Add the warm milk and mix until a shaggy dough forms.

Turn the dough out onto a lightly floured surface and knead for about 5-7 minutes, until it becomes smooth and elastic.

First chill: Shape the dough into a rectangle, wrap it tightly in plastic wrap, and chill in the refrigerator for at least 2 hours, or preferably overnight. This relaxes the gluten and makes the dough easier to work with.

Prepare the butter: While the dough is chilling, place the cold butter cubes between two sheets of parchment paper. Use a rolling pin to pound and roll the butter into a thin, roughly 6x8 inch rectangle. Keep it chilled.

Laminate the dough (first turn): On a lightly floured surface, roll the chilled dough into a 12x16 inch rectangle. Place the chilled butter rectangle in the center of the dough, leaving a border around the edges.

Fold the dough over the butter like a letter, enclosing the butter completely. Pinch the seams to seal.

Gently roll the dough into a 12x16 inch rectangle again. Be careful not to press too hard, or the butter will squish out.

Second fold: Fold the dough into thirds again (like a letter). This is your first 'turn.' Wrap in plastic wrap and chill for 30 minutes.

Repeat (second and third turns): Repeat the rolling and folding process two more times, chilling the dough for 30 minutes after each turn. This creates all those beautiful layers.

Final chill: After the third turn, wrap the dough and chill for at least 2 hours, or preferably overnight.

Shape the croissants: On a lightly floured surface, roll the chilled dough into a large rectangle, about 1/8 inch thick.

Trim the edges to create straight lines.

Cut the dough into triangles. I like to make mine about 4 inches wide at the base.

Place a chocolate baton or a few chocolate chips at the base of each triangle.

Roll the dough up from the base to the point, gently stretching the dough as you roll.

Place the shaped croissants on a baking sheet lined with parchment paper.

Proof: Cover the croissants loosely with plastic wrap and let them rise in a warm place for about 1-2 hours, or until they're puffy and almost doubled in size.

Egg wash: Preheat your oven to 375°F (190°C). Whisk the egg with a tablespoon of water. Gently brush the risen croissants with the egg wash.

Bake: Bake for 18-22 minutes, or until the croissants are golden brown and cooked through.

Let them cool slightly on a wire rack before serving. They are incredible when served warm!