Thaw the spinach, squeeze it out, season with salt, pepper and nutmeg. Halve the cocktail tomatoes, peel the garlic and press down with the side of the knife.
Place the spinach in a flat baking dish, place the frozen salmon fillets on top, place the tomato halves and the garlic around them. Brush the top of the fish with pesto, then add more pesto flakes between the tomatoes.
Bake in a preheated oven (200 ° C top / bottom heat; 180 ° C fan oven) for 25-30 minutes.