> pancakes

Is this a frittata-style baked pancake? I've made rye pannukakku from the family cookbook here in the US Midwest but never seen any Finnish pancake with spinach or nettle.

Not quite. You take Finnish pancake batter (unleavened, a bit thicker than French crepes) and add blanched, finely chopped spinach or nettles.

https://scandicuisine.com/stinging-nettle-pancakes/ looks quite reasonable though most Finns would not use a blender for this.