Heat the oven to 220C/425F/gas mark 7.
Cut the potatoes in half (or quarters if they’re large), then place in a pan of salted water. Bring to a boil and cook for 12-15 minutes, until tender. Drain and lightly crush with a potato masher or fork.
While the potatoes are cooking, put another pan of water on the heat and bring to a bare simmer (no bubbles).
Toss the asparagus in 1 tbsp of oil in a baking dish. Add a splash of sherry or red wine vinegar and the smoked paprika, and season with salt and pepper. Roast in the oven for 8-12 minutes (depending on the thickness), until tender.
Heat 1 tbsp of oil in a frying pan. Add the onion and cook slowly for 10 minutes to soften without colouring. If it starts to catch, add a splash of water and reduce the heat. Crumble in the chorizo and increase the heat slightly. Fry for 4-5 minutes to cook the chorizo through, then stir in the potatoes and warm through. Add the parsley and season to taste.
Add a good splash of vinegar to the simmering pan of water. Crack the eggs into individual ramekins or small bowls. Use a spoon to swirl the water so it looks like a whirlpool and gently drop the eggs into the centre, one at a time, and poach for 3 minutes, then remove with a slotted spoon and drain on kitchen paper. Sprinkle the eggs with a little salt before serving them on top of the potatoes and asparagus.