In a saucepan put 100 ml of milk to boil.
When it starts to boil, add 50 g of flour and mix well until it becomes a hard paste.
Put the scalded dough in a bowl and let it cool a bit.
Mix the yeast with 2 teaspoons of sugar and a little warm milk.
Put the yeast over the scalded dough and mix a little to blend then leave to rise for approx. 15 minutes in a warm place away from electricity.
Mix the yolks with the salt, add the rest of the milk (warm), sugar and vanilla sugar.
Pour the liquid mixture over the yeast.
Sift the flour 2-3 times then add it over the yeast.
Knead the dough for 10 minutes on the work table lined with flour (with great patience because it is a fairly sticky dough at first).
Start adding the oil little by little and knead the dough well until you have incorporated all the oil and the dough no longer sticks to your hands.
Leave the dough to rise for 90 minutes in a warm place covered with a towel.
Knead the dough for a few seconds just to remove the air then divide it into 6 approximately equal pieces.
Spread each piece in a circle.
Cut each circle into 4 triangles.
Place a square of finely chopped chocolate at the base of each triangle and then roll tightly towards the top.
Put the croissants in a tray lined with butter and baking paper and let them rise for another 15 minutes (I had 2 large trays)
Bake the croissants in the preheated oven for about 30 minutes on low heat.
While they are hot, grease them with honey diluted with a little warm water and then sprinkle with caster sugar.