How to make
Whisk the butter and sugar well and add the eggs one at a time, along with the hartshorn that you've dissolved in advance in the vinegar, vanilla, and whip the mixture until finished. Add flour so as to get a soft dough that you can roll out. Divide the dough into balls.
Roll out each ball into a sheet, and cut out biscotti with an appropriate form. Bake the homemade holiday biscotti on high heat, but be careful not to brown them.
Thus prepared homemade biscuits can be used to make various desserts with cream or just served as is with coffee.
