Preheat the oven to 200°C.
Finely slice and rinse the leek. Cut broccoli florets into smaller pieces, and grate the stalk if using.
Heat a frying pan with oil then sauté the leek for 5-6 minutes until soft. Set aside.
Beat together eggs and cream in a bowl.
Generously grease a 21cm springform pan, including the sides.
Place the potatoes into a pot of salted water, bring to the boil and boil the potatoes until soft and fork tender.
Once soft, drain the potatoes. Place the drained potatoes (still hot) into the prepared cake tin and use the bottom of a clean mug to smash the potatoes.
When the potatoes have cooled slightly, use your fingers to smooth them out over the base of the tin and push the potato ⅓ of the way up the sides of the tin to create a crust. Brush with oil and season with salt.
Place the potato base into the oven to cook for 15 minutes.
Remove the potato base from the oven and sprinkle over the sautéed leeks, broccoli, and spinach and half the grated cheese.
Pour over the beaten egg mixture. Sprinkle the remaining cheese on top.
Reduce the heat of the oven to 190 degrees and bake for 25-30 minutes until golden and softly set in the middle. Best served immediately.
