For the meat marinade, stir all the ingredients, brush the roast with it all around, leave in the refrigerator with the lid closed for one night. Remove from refrigerator 2-3 hours before roasting. Preheat the stove to 250 °C. Wipe marinade off meat, set aside. Season roast with salt, place fat side down on a large baking sheet and roast in the bottom half of the oven for 20 minutes. Then place roast and roast for another 10-15 min.
Brush seared chop roast with some of the marinade, place on grill rack of kettle grill, close grill lid, let cook for 1 1/2 hours. In between, brush with the remaining marinade.
Stove-top variation: sear roast as described, but reduce heat to 100 degrees after 25 minutes. Then allow meat to marinate for 1 3/4 to 2 1/2 hours. Core temperature should be 60 degrees. Brush roast with marinade in between. Roast can be kept warm in 60 degree oven for one hour.
For the baked potatoes, pierce the potatoes a few times with a fork. Wrap them individually in aluminum foil, place them on a baking sheet and bake them for about 1 hour in the oven heated to 200 degrees.
Remove the potatoes from the foil and score them crosswise on one side with a kitchen knife. Mix the crème fraîche with the chives and spread on the potatoes.
As a variation, the potatoes can also be baked without foil. The skin then remains