Wilt the spinach. Heat the olive oil in a large frying pan over a medium heat. Add the spinach in handfuls, stirring gently. You will hear a soft hissing sound as the water releases. Within 2-3 minutes, the leaves will collapse into a dark, silky mass. Transfer the cooked spinach to a colander and press down firmly with the back of a spoon to remove as much liquid as possible. You want it to feel quite dry to the touch.

Sweat the aromatics. In the same pan, add the diced onion and cook over a medium-low heat for 5-6 minutes, until it turns translucent and smells sweet. Add the minced garlic and cook for another 30 seconds until fragrant. The kitchen should now smell warm and savoury.

Prepare the custard. In a large mixing bowl, crack the eggs and whisk them vigorously until they are pale and frothy, with a slight ribbon texture when you lift the whisk. Pour in the double cream and whisk again until fully combined. The mixture should look smooth and uniformly yellow.

Assemble the filling. Roughly chop the squeezed spinach so there are no long, stringy leaves. Add the spinach, sautéed onion, crumbled feta, and grated cheddar to the custard. Sprinkle in the nutmeg, salt, and pepper. Stir gently with a wooden spoon until everything is evenly distributed. The feta will create small white pockets throughout the mixture.

Bake the quiche. Preheat your oven to 180°C (160°C fan). Grease a 23cm round pie dish (or a 20cm square baking dish) with butter. Pour the mixture into the dish and spread it evenly. Bake for 35-40 minutes. You will know it is ready when the top is a deep golden brown, the edges are set, and the centre gives a slight, gentle wobble when you shake the dish, like a firm jelly.

Rest before serving. Remove the quiche from the oven and allow it to rest on a wire rack for at least 10 minutes. During this time, the residual heat will finish setting the centre completely. The aroma will fill your kitchen with a rich, eggy, cheesy scent that signals comfort is imminent.