Spickzwiebel what kind of onion is that????

We visited Kevelaer, just over the border in Germany yesterday. Sunny wheather but icy cold wind. Browsing in the local bookstore I stumbled on a regional cookerybook: Badische Kueche, Rezepte, Braeuche und Geschichten im Jahreslauf.
Of course, I bought it for just under ten euro. Full of great traditional German recipes and nicetoknow stories.
As I had bought fresh trout on the Dordrecht Market Friday when shopping with my friend Caroline (wonderful salad in Zest), I looked up the traditional Blue Trout, or Truite bleu, or Forelle Blau.
One needs trout, of course, and a lemon, and vinegar, salt, pepper, thyme and butter, but also something called Spickzwiebel. Luckily, they explain for the poor not-Badener cook. You peel and halve an onion, take a laurelleaf and pin it with a clove on the onion. And that is your Spickzwiebel.
I did not follow the recipe any further, because they make you boil your trout in five liters water. Hello? Should I throw them in my hottub? Is that what they mean with Baden? Four trouts in five liters water with the vinegar and all the rest? Am I making soup?
Instead I put a slice lemon and a fresh branche of thyme in their tummy. I placed them in an ovenproof dish. In a small pan I heated Pfalzer white wine, peppercorns, the spickonions, more thyme and lemon and salt, but not the 3 tablespoons from the recipe, just a dash. I let it boil for a while and then poured it over the trout, who then went into the oven for 20 minutes at 225 degrees C. They were just ready. Cookingtime depends on size and number of fish.
Delicious. Might add a dash of good vinegar the next time just to try.