Preheat your oven to 375°F (190°C). Place your pie dish on a baking sheet for easy handling, then fit your crust into the dish and gently press it into the corners. Chill in the fridge while you prepare the filling.
Heat a tablespoon of olive oil in a sauté pan over medium heat. Add the chopped spinach and cook, stirring, until wilted and vibrant green, about 2-3 minutes. Remove from heat and let cool slightly.
In a large mixing bowl, whisk the eggs until smooth and slightly frothy. Pour in the heavy cream, then add a pinch of nutmeg, salt, and pepper. Whisk again until fully combined and the mixture is light and creamy.
Stir the cooled spinach into the custard mixture, breaking it apart with the whisk. Fold in the grated cheddar cheese gently, ensuring even distribution.
Pour the filling into the prepared crust, spreading it evenly with the back of a spoon or spatula. Cover the edges of the crust with foil or a pie shield to prevent over-browning.
Bake in the oven for 35-40 minutes, until the top is golden brown and the filling is just set with a slight jiggle in the center. The edges should be crispy and the crust golden.
Remove the quiche from the oven and let it rest for 10 minutes. This helps the filling firm up, making it easier to slice cleanly.
Slice the quiche with a sharp knife, serve warm or at room temperature, and enjoy the creamy interior combined with crispy crust and savory greens.