Fry the pancetta cubes over medium heat until crispish (it can make things easier if you use olive oil with the butter, say 1/2 tbsps). Add the white wine and the peas, stirring around until the wine has mostly evaporated. Add the chicken stock, a good twist of black pepper, and a pinch of salt. Simmer until the peas are heated through, 5 - 8 minutes if frozen peas, 15 minutes if fresh, uncooked peas. They should be the small, sweet peas known as petit pois. Taste and adjust seasoning, add a tsp of sugar if you like them sweeter.