Turn the oven on to 200 degrees celsius, and put a large saucepan of water on to boil. When the water is bubbling add the chopped potatoes and allow to par-boil for 5 minutes, until just starting to soften.
Drain par-boiled potatoes and transfer to a large baking tray. Mix potatoes with 2 tablespoons of oil, a liberal sprinkling of pepper and the herb salt.
Put potatoes in the oven for 30 minutes, until browning and starting to crispen.
Meanwhile, heat 1 tablespoon of oil in a large, deep saucepan over a medium heat. When hot add the chopped onions and cook for 5 minutes, stirring regularly, until starting to soften and become translucent.
Add the chopped peppers and season with a dash of salt and pepper. Cook for a further 4-5 minutes, stirring regularly. If it starts to dry out and stick at any point add a splash more oil.
Stir in the sliced chorizo, diced garlic, and sliced mushrooms. Allow to cook, stirring regularly, for another 5 minutes, until the flavours are well mixed and everything has softened (but not too mushy!). If the potatoes aren't done yet, take the pan off the heat until they're ready.
Once the potatoes have browned and crisped up, stir them into the pan and allow to cook for a further 3-4 minutes.
Stir the spinach into the pan in batches until starting to wilt (around 1 minute).
Create four small wells in the pan, and crack the eggs into these wells. Cover the pan and allow to cook for 5 minutes. When the eggs are nearly done, grate or crumble over your cheese of choice. Remove from the heat when the eggs are done - the whites should be hardened but the yolks still soft and runny.
Serve with sliced avocado, chilli flakes, spring onion, coriander or parsley, and a drizzle of hot sauce.