Thaw the spinach in a saucepan over medium heat and simmer gently for a few minutes. Add the garlic and feta and season. Continue simmering until the feta has spread out nicely.
Then put half of it in a baking dish, top with the salmon and the rest on top. Finally, grate the Gouda, mix with sour cream and spread over it. Finally, spread the pine nuts over it and then put them in the preheated oven (180 ° C). After about 45 minutes, when the surface is golden brown, the lasagna is ready.