Thats really hard to choose,
I like to make
oatmeal / walnut/ chocolate chip
Hhahahahaha I think we like cookies
Here is a link, I think I would like to make cranberry biscotti , https://kristineskitchenblog.com/classic-biscotti-recipe/
black walnut cookies. i only make them once or twice a year and only a double batch as the rest of the time we bake hundreds of cookies at a time. normally every other week or so Mom will be making more. this past week she'd made chocolate cherry and chocolate macadamia nut cookies. i've been good and only eaten three of them since she made them but i have to admit that i love cookie dough so i did have a few small lumps to make sure they were ok. you know. quality control is very important.
I really think about any basic cake recipe I normally use can be altered to become cookies just by increasing the butter and decrease the milk or water. Not sure if I exactly have a favorite because really cookies make me think about crushing them to make whiskey balls.