Start by preheating your oven to 200°C (390°F). In a large bowl, combine 250g plain flour and a pinch of salt. Cut the chilled unsalted butter into cubes and add them to the dry ingredients.

Use your fingertips to rub the butter into the flour until the mixture resembles coarse breadcrumbs. Add a splash of cold water and mix until a dough forms.

Wrap the dough in cling film and refrigerate for about 30 minutes.

While the dough chills, heat a drizzle of extra virgin olive oil in a frying pan over medium heat. Add the finely chopped onion and cook until softened and slightly golden. Add the minced garlic and cook for another minute, just until fragrant.

If you’re using butternut squash, peel and chop it into small cubes. Add it to the pan and cook until tender, around 10-15 minutes. Season with salt, pepper, and a dash of smoked paprika.

If using wild mushrooms, sauté them until they are golden brown and have released their moisture.

In a separate bowl, whisk together the six free-range eggs and heavy cream. Stir in the grated sharp Cheddar cheese, crumbled goat cheese, and fresh spinach. Finally, add the cooked onion and butternut squash (or mushrooms) to this mixture.

Remove the dough from the fridge. On a lightly floured surface, roll out the dough into a circle large enough to fit a 23cm (9-inch) pie dish. Gently lift the rolled dough and place it into the dish, pressing it into the edges.

Pour the egg mixture into the crust, spreading it evenly. Bake in the preheated oven for 35 to 40 minutes or until the quiche is set and golden on top.

Once it's done baking, allow the quiche to cool for a few minutes before slicing. This allows the flavors to meld. Serve it warm or at room temperature.