Preheat oven to 350ºF (180ºC)In a bowl we mix the melted butter with the sugar.Then we incorporate the eggs and beat a little more. Then we add the flour, baking soda and lemon zest. Mix all the ingredients until the dough is well united. Take a while since most of the ingredients are dry.We incorporate the essence of vanilla, almonds, chocolate chips or any other ingredient that you use and mix more.We put the dough on the table or table and give bread or pudding not very high.Place the dough on a lightly greased baking sheet.Bake for 30 minutes.Remove from the oven and let cool for a while.We cut sticks and place them on the baking sheet again for 10 more minutes. This second baked is to toast the biscottis.Enjoy!