Start by preheating your oven to 200°C (390°F) and lining a baking sheet with parchment paper. Sauté the chopped spinach in a skillet over medium heat for 2-3 minutes until wilted and vibrant green, then let it cool slightly.
In a mixing bowl, combine the softened cream cheese, grated cheddar, and minced garlic. Mix until smooth and creamy, then fold in the cooled, chopped spinach. Add the beaten egg, thyme, salt, and pepper, stirring until well combined.
On a lightly floured surface, roll out the puff pastry to about 0.5 cm (1/4 inch) thickness. Using a cookie cutter or sharp knife, cut out 3-4 inch circles, aiming for even, clean edges for sealing.
Place about a teaspoon of the spinach filling in the center of each pastry circle. Fold the pastry over to form a half-moon shape, then press the edges together to seal tightly. Use a fork to crimp the edges for extra security.
Arrange the filled puffs on the prepared baking sheet, spacing them at least 2 inches apart. Brush the tops with the beaten egg wash to give them a shiny, golden finish.
Bake in the preheated oven for 15-20 minutes, or until the puffs are golden brown and crispy. Keep an eye on them—if the edges brown too quickly, tent with foil to prevent burning.
Once baked, remove the puffs from the oven and let them rest for 5 minutes on a wire rack. This allows the filling to set slightly and makes them easier to serve.
Serve the spinach puffs warm, optionally garnished with fresh herbs or a squeeze of lemon for added brightness. Enjoy their crispy exterior and tender, cheesy spinach filling.
