Quarter potatoes and set on a sheet pan in 1 layer to dry. Once they're dry, place potatoes in a bowl. Mash with a fork until broken up but not smooth. Add pepper, chives, thyme and tarragon. Season with salt. Mix well. Add the oil a half cup at a time. You may find you do not need all the oil. Add lemon zest, if using. Mix well.
Chef's note: Cook the potatoes whole so they don't get water logged and dilute the flavor.