Step 1: Make the Dough : In a large mixing bowl, combine warm milk, sugar, and yeast. Let sit for 5 minutes until slightly foamy. Add flour, salt, softened butter, and the egg. Mix until a soft dough forms. Knead for about 5–7 minutes until smooth. Shape into a ball, cover with plastic wrap, and refrigerate for 30–40 minutes.

Step 2: Prepare the Butter Block : Place cold butter between two sheets of parchment paper. Use a rolling pin to flatten it into a 7x7 inch square. Chill the butter block until firm but pliable (about 20 minutes).

Step 3: Laminate the Dough : Roll the chilled dough into a 10x10 inch square. Place the butter block in the center diagonally, so it looks like a diamond on the dough square. Fold the dough corners over the butter to completely encase it. Roll the dough out into a rectangle (about 20x10 inches). Fold the bottom third up and the top third down — like folding a letter. Wrap in plastic wrap and refrigerate for 30 minutes. Repeat this rolling and folding process twice more, chilling for 30 minutes each time.

Step 4: Shape the Croissants : After the final chill, roll the dough into a large rectangle (about ¼ inch thick). Cut into long triangles (base about 4 inches wide). Starting from the wide base, roll each triangle tightly toward the tip. Curve the ends slightly to form a crescent shape.

Step 5: Proofing :Place croissants on a parchment-lined baking sheet. Cover loosely with plastic wrap and let them rise at room temperature for 1½–2 hours until puffy and doubled in size.

Step 6: Baking : Preheat the oven to 400°F (200°C). Brush croissants with egg wash (egg + milk mixture). Bake for 20–25 minutes or until golden brown and flaky.

Step 7: Serving : Let cool slightly. Serve warm with strawberry jam on the side or spread inside. Optionally, dust with powdered sugar for an elegant finish.