- Preheat the oven to 180°C.
- Peel the potatoes and cut into smaller pieces. Bring to a boil together with the cauliflower florets in salted water for 20-25 minutes until soft. Drain and mash with a potato masher.
- Stir in the egg, butter, grated cheese and panko. Season with salt and pepper.
- Line a ⌀ 20 cm baking tin with baking paper. Pour in the potato mixture and level the surface with the back of a spoon. Place in the oven for 30 minutes.
- Finely chop the red onion.
- Take out of the oven and add the chopped red onion on top. Add the other toppings so each quarter of the pie has a different toppings. Drizzle with olive oil and season with salt and pepper. Place back in the oven for 10 minutes until the toppings are cooked.
- Take out and cut in quarters. Take a piece and enjoy the other quarters later in the week (just cover in tin foil and pop back in the oven for 10 minutes).
Add other toppings of choice.