Hello there, and happy June! I was on vacation (a real one!) for most of May, but I’m back now with 5-2: Old-Fashioned Oven Pancake. There’s not a lot that goes into this dish (just 4 ingredients), and it’s probably better/more commonly known as a German pancake and/or a “Dutch baby”.
So far, this is the only mention of lingonberries that I’ve seen in this whole book–I always think of them as something you only see in jam form at IKEA, but according to Wikipedia they are grown in multiple regions including North America (not just Europe/Scandinavia). They’re tough to find fresh here, but frozen seems to be widely available.