1. Preheat the oven to 390°F (200°C). Line a baking sheet with baking parchment and set aside. Peel and dice the onion and garlic finely. Wash and dry the spinach – if the stems are too thick remove them, cut larger leaves into smaller pieces. Set aside.

2. Heat up a large frying pan without any fat or oil. Add the pine nuts and toast until fragrant and lightly browned. Remove from the pan and let cool down. Add some oil to the still-hot pan and heat up. Add the diced onion and cook until soft and glossy. Add the garlic and let cook as well for some time – but do not burn it or it will taste bitter. Add the washed spinach and mix everything until the volume of the spinach is mostly gone. Add the lemon juice and season with salt, and pepper to your liking. Remove from the heat and let cool down a bit.

3. Crumble the feta cheese to get small pieces and add together with the toasted pine nuts to the pan with the spinach – mix until well combined. Roll out the puff pastry sheet and spread the filling evenly on top – make sure you leave a strip (about 0.8 inches/2cm) on one of the longer sides free of filling. Brush that part of the puff pastry with some water and roll up everything from the opposite side to get one long log – if you end up with one fat short log you did something wrong ;) Cut that long log into 10-11 equal slices and place them swirl side up with some space in between on the prepared baking sheet. Brush the sides and tops of the rolls with whisked egg and bake for 16-18 minutes or until the sides of the spinach rolls look crunchy and golden. Take out of the oven and let cool down a bit on the baking sheet. Serve warm (or cold) with some yogurt sauce.