Peel and wash the potatoes, cut them into pieces and cook them covered in salted water for about 20 minutes. Add frozen spinach and cook for about 10 minutes.
In the meantime, preheat the oven (electric cooker: 200 °C/circulating air: 180 °C/gas: see manufacturer). Line a tray with baking paper. Cut Pancetta finely. Grate the pecorino finely. Mix both and spread them in 8 heaps on the baking tray. Press flat to form talers (approx. 8 cm Ø). Bake in a hot oven for 10-12 minutes.
Bring approx. 2 l water and vinegar (no salt!) to the boil in a wide pot. Beat the eggs one after the other into a cup, slide them one by one into the boiling water and poach in it for about 4 minutes. The water must not boil during this process, as the egg whites would run apart due to the fizzing.
Bring butter and milk to the boil briefly. Add peas to the potatoes and cook for about 3 minutes. Remove the eggs with a skimmer and let them drip off on kitchen paper. Drain the potatoes in a sieve, drain briefly and put them back into the pot. Add butter and milk and mash everything coarsely. Season to taste with salt and nutmeg. Arrange mashed potatoes with cheese-ham chips and eggs. Season with pepper.
TIP: Poach eggs for beginners: Use very fresh eggs. The egg white is then still viscous and envelops the yolk like a protective cover. This is guaranteed to work: Line cups with cling film and coat with oil. Beat the eggs one by one and let them slide in carefully. Tie with kitchen string and poach.