Preheat and Prepare: First, preheat your oven to 200°C (180°C fan) and line a large baking sheet with baking parchment.

Squeeze the Spinach: Place the thawed spinach in the centre of a clean tea towel or several layers of strong kitchen paper. Gather the corners and twist tightly over the sink, squeezing until no more liquid comes out. You should be left with a small, dense ball of spinach. Set it aside.

Sauté the Aromatics: Heat the olive oil in a small frying pan over a medium heat. Add the finely chopped shallot and cook for 3-4 minutes until softened but not browned. Add the minced garlic and cook for another minute until fragrant. Remove from the heat and let it cool for a few minutes.

Combine the Filling: In a medium mixing bowl, combine the softened cream cheese, crumbled feta, and grated Parmesan. Add the squeezed spinach, the cooled shallot and garlic mixture, nutmeg, pepper, and a tiny pinch of salt. Mix everything together until well combined. I find that it's best to let the filling cool completely before using it; this prevents the pastry from becoming warm and greasy.

Assemble the Puffs: Unroll your sheet of puff pastry onto a lightly floured surface. Cut the sheet into 12 equal squares (a 4x3 grid). Spoon about a tablespoon of the spinach mixture into the centre of each square.

Seal and Crimp: Brush the edges of each square with a little of the beaten egg. You can fold them into triangles or bring two opposite corners together to make a parcel. Press the edges firmly to seal, then use the tines of a fork to crimp the edges closed. This ensures the delicious filling stays inside while baking.

Prepare for Baking: Carefully transfer the assembled puffs to your prepared baking sheet. Brush the tops all over with the remaining beaten egg – this will give them a lovely golden shine. If you like, sprinkle with a few sesame or poppy seeds.

Bake to Perfection: Bake in the preheated oven for 20-25 minutes, or until the puffs are deeply golden brown, well-risen, and you can see the filling bubbling slightly at the seams. Let them cool on the baking sheet for a few minutes before transferring to a wire rack. They are wonderful served warm.