Preheat oven to 180 C / Gas 4. Lightly grease a medium baking dish.
Melt butter in a frying pan and cook and stir onion and garlic until translucent. Add spinach in batches and cook until wilted. Season with nutmeg, salt and pepper to taste and cook until all liquid has evaporated. This is important, because the pancakes can get mushy if the spinach is too moist. Transfer spinach to a bowl and set aside to cool.
In the same pan fry chorizo until crispy and brown. Pour off fat. In the meantime heat milk and goat's cheese in a small saucepan, stirring until the cheese has melted and the mixture is smooth. Add soured cream and season with salt and pepper to taste.
Add 4 tablespoons of the goat cheese sauce and eggs to the cooled spinach and mix well. Evenly spread spinach mixture over each pancake, sprinkle with chorizo and roll up. Place the rolls side by side into the prepared dish, spoon the remaining cheese sauce on top and sprinkle with Parmesan cheese.
Bake for 25 to 30 minutes until the filling is set and the rolls are golden brown on top.