Place the potatoes in a large pot of extremely well salted water. Add the baking soda, then cook until a knife slides through the largest potato. This could take 10-25 minutes, depending on the size of the potatoes.
While you're waiting, preheat the oven to 200C/400F.
In a large bowl, combine the dry ingredients for the herb crust. Add the oil and stir to combine. Add the parmesan and stir again.
Once the potatoes are cooked, drain them (setting a small amount of cooking liquid aside). Use gloves and work quickly to chop each potato into bit sized slices, then place it into the bowl. Heat and a bit of liquid will help the herb crust adhere to the potatoes.
Continue until all the potatoes are in the bowl, then toss to coat. You can cover the bowl with a large chopping board and shake them up a little, if you like.
Transfer the potatoes to a large baking tray and spread them out. If any herb crust isn't attached to a potato, plop it atop one. Bake for 20 minutes, then try to flip each potato if you can. If they're all stuck, leave them and return them to the oven. Bake for an additional 20 minutes or until golden brown.
Sprinkle with some extra salt and serve!