Defrost the puff pastry and spinach. Preheat the electric stove to 200 °C. Rinse a baking tray with cold water.
Place the puff pastry sheets side by side and roll them out into a rectangle a little larger than the baking sheet. Place dough on the baking sheet.
Peel the onion and cut into thin rings. Roughly chop the spinach leaves and spread evenly on the puff pastry. Season with salt, pepper and nutmeg (freshly grated).
Place the salmon slices on the spinach leaves and drizzle with the juice of one lemon. Put the sour cream as small blobs on top. Last but not least, spread the onion rings evenly on the pizza and season everything together repeatedly with salt, pepper and nutmeg (freshly grated).
Bake the pizza on the lowest rack at 200 °C for 40-45 min. until crispy. Rinse the basil, shake dry and pluck the leaves. Divide the baked pizza into even pieces and garnish with the basil leaves. Serve.
Tip: Did you know that one bowl of spinach already covers the entire daily requirement of vitamin K and beta-carotene?