Culinary specialty of the Hunsrueck region - Spiessbraten (just in time for grilling season)

On my recent trip to Germany, I had to sample of course the regional specialties. Even though I grew up on them, it is nice to go back and be treated to the food rather than prepare it on your own.
In time for grilling season, I want to introduce the Spiessbraten. This dish is fairly simple to prepare since it is basically a piece of meat, marinated in raw onions, pepper and salt,then grilled on a traditional wood fire. You can use either beef or pork, but most people use pork since it is more affordable. You can use pork tenderloin, T-bone or ribeye steak as well as beef sirloin. The onion is usually a traditional yellow onion, sliced thinly. The meat is spiced with salt and pepper to taste, then added to a good amount of onions and marinated for a minimum of 5 hours, preferably overnight.
The traditional wood fire is prepared and the meat is put on a roast and grilled over the fire. Traditionally the Spiessbraten is served with radish salad or a dill pickle and a roll or a slice of hearty bread. Some pictures from my hometown, but also various ways to prepare the Spiessbraten are shown on this link.
My own Spiessbraten dish is shown below.

copyright Durhamonthecheap - traditional Spiessbraten dish

A brief note about the origin of Spiessbraten. The dish is supposed to have originated when local agate cutters returned from Brazil. During the late 19th century, agate deposits ran out around Idar-Oberstein and people sought new material in other countries, among them Brazil. While there, they picked up the traditional BBQ style over the open fire and when returning to the Hunsrueck introduced this way to prepare meat. Not sure whether this is the true origin of Spiessbraten, but I can tell you that this is still my preferred way to grill meat and to this day, I can only eat grilled meat from charcoal or gas grills with lots of sauce. The traditional wood fire introduces a specific flavor into the meat and meat grilled any other way smells and tastes like a chemical concoction to me.