First, make the laminated pastry dough.

Sift the flour into a large bowl. Add the sugar and the 2 tablespoons of butter. Rub the butter into the flour with your fingertips until the mixture resembles wet sand.

Add the yeast and make a well in the center.

Dissolve the salt in the lukewarm milk, then gradually add the milk to the flour mixture, kneading as you go, until the dough no longer sticks to your hands.

Transfer the dough to a lightly floured work surface and knead for a few minutes. If necessary, sprinkle with a little extra flour.

Place the dough in a lightly floured bowl, cover well and leave it in a warm place until it doubles in size. This should take about 1 hour if kept somewhere warm.

Transfer the risen dough to a work surface.

Using a rolling pin, roll it into a thick rectangle measuring approximately 40 × 15 cm.

Place the 100 g of butter in the center of the dough.

Fold the dough over the butter, completely enclosing it. Gently press and roll the dough with the rolling pin until it returns to approximately its original 40 × 15 cm size.

Fold the dough into thirds, like a letter, and cover it with plastic wrap.

Place it in the freezer for 15 minutes.

Roll the dough out again and, turning it so that a different corner is facing you, fold it into thirds once more.

Repeat this process twice more, resting the dough in the refrigerator for 15–20 minutes after each fold.

Once the dough has completed its final resting period, roll it out into a rectangle approximately 30 × 20 cm.

Cut the dough lengthwise into 2 strips, then cut each strip into 6 pieces, giving you 12 pieces of dough in total.

Brush the pieces lightly with beaten egg.

Place one rectangular piece of chocolate on each piece of dough.

Fold the dough over the chocolate, enclosing it completely.

Place each croissant seam-side down and gently press the edges together to seal the chocolate inside.

Arrange the chocolate croissants on a buttered baking sheet.

Cover loosely with plastic wrap or a clean kitchen towel and leave in a warm place for approximately 30 minutes, until the croissants have puffed up.

Preheat the oven to 200°C (400°F), using the convection/fan setting.

Brush the croissants once more with beaten egg.

Bake for approximately 15 minutes, until puffed and beautifully golden brown.