Thaw the puff pastry and the spinach leaves. Then preheat the oven to 200 ° C top / bottom heat.
Mix the sour cream with the flour, egg and cheese and season with salt, nutmeg and pepper. Squeeze the spinach and cut the salmon into small pieces.
Halve the pastry sheets and place the pastry squares in the muffin tins. Layer the spinach and salmon and cover with the mixed cream. Then fold up the tips of the dough sheets at the top. If there are still open areas on the long sides of the dough sheets, do not worry - they close during the baking process and the liquid does not run out.
Bake the muffins for about 30-35 minutes and then serve them warm.