Preheat your oven to 190°C (375°F). Lightly grease your muffin tin or line it with paper liners, then set aside. Roll out your pastry sheet on a lightly floured surface until it's about 1/8 inch thick, and use a pastry cutter or glass to cut out circles slightly larger than your muffin cups.
Press each pastry circle gently into the muffin cups, lining the bottom and sides. Chill the tray in the fridge for 10 minutes to help the crust set and prevent shrinking during baking.
In a mixing bowl, whisk together the eggs and heavy cream until smooth and slightly frothy—this creates a silky custard base. Stir in the chopped spinach, shredded cheese, herbs, and season with salt and pepper to taste.
Remove the muffin tray from the fridge and evenly spoon about 2 to 3 tablespoons of the filling into each pastry-lined cup, filling them just below the top to allow for puffing.
Place the tray in the oven and bake for about 20-25 minutes, or until the tops are golden brown and puffed, and the filling is set but still slightly wobbly in the center. You'll hear a gentle bubbling sound as they bake.
Once baked, remove the tray from the oven and let the mini quiches rest on a wire rack for 5 minutes. This allows the filling to set fully and makes them easier to remove without breaking.
Gently lift each mini quiche out of the tin using a small spatula or knife. Serve warm or at room temperature, garnished with extra herbs if desired, and enjoy the flaky crust paired with creamy, cheesy filling.
