1. Beat the butter at room temperature with the sugar until white, add the vanilla essence, a pinch of salt and the egg, mix well. Sift the flour with the Royal yeast and add it to the previous mixture. Finally add the chocolate chips. Form a tender dough ball without kneading it too much. Let it rest in the refrigerator for at least 30 minutes.
2. Roll out the dough half a centimeter thick, cut circles and put them on a greased baking sheet. Cook at 190º C for approximately 7 minutes. Tips (advice): You will realize that they are ready when the edges of the cookies begin to appear slightly golden. It is important not to wait for them to take on color on top, otherwise when they cool they would be very hard.
3. It is important to let the dough rest in the refrigerator so that it maintains its shape when cooked. To stretch the dough we can help ourselves with a little flour on the counter, but be careful, without overdoing it, because otherwise the cookies would turn out like stones.
4. You can use either chocolate chips, which are available in almost any supermarket, but you can also chop up bar chocolate.