Combine all the herbs and spices in a bowl and set aside.
Heat a large Dutch oven over medium high heat. When it’s hot, add the oil.
Liberally season the ribs with salt and then brown them in batches and set aside.
Reduce heat to medium low and add the onions.
Cook the onions for a few minutes until they just start to brown.
Add half of the garlic and cook for another minute.
Return short ribs to the pot. Try to keep the bone-side facing down.
Sprinkle the spice mixture over the meat. If you don’t mind getting your hands dirty, you can rub the mixture evenly over each rib.
Sprinkle remaining garlic over the top of the ribs.
Add enough beef stock to cover the ribs about 1/2 to 2/3 the way up their sides.
Cover, place in the oven and braise for 2-2 1/2 hours.
While the ribs are cooking, make the potato and parsnip puree. Fill a medium pot with cold water and add some salt.
Add the potatoes and parsnips and set on the stove over medium high heat.
When the potatoes have cooked, drain off the water, add the butter, sour cream and milk and puree with an immersion blender. You could also do this in a food processor. Mashing by hand works too, but the parsnips require a bit more elbow grease to get properly mashed.
Season with salt and pepper. Cover and set aside.
Test the ribs with a fork to see if they are done. They should be very tender and just about falling off the bone. You should be able to easily slide the rib off the bone, but you don’t want to cook it so much that the connective tissue surrounding the bone completely dissolves.
Place the ribs on a platter and cover with foil.
Strain the cooking liquid into a large measuring cup and skim off the fat.
Add the sauce to a small pot. You have a few choices here. If you are satisfied with the flavor and viscosity, you can leave the juice as is and adjust the seasoning. If you prefer a more concentrated flavor, you can reduce the sauce by boiling. If you like a thicker sauce, you can whisk in a bit of flour while reducing until you get the sauce thickened to your liking.
To serve, make a bed of the pureed potatoes and parsnips on a large plate or in a shallow bowl. Place one rib, with bone, in the middle of the bed. Pour sauce over the meat and sprinkle with parsley for garnish.