Heat 4 teaspoons of the olive oil in a large saucepan. Add the onions and a pinch of salt. Fry the onion over a low heat until soft and translucent. Add the sausage, turn the heat to high and cook until the sausages are browned all over. Add the Marsala and let it evaporate.
Blanch the broad beans and peas in salted boiling water for 30 seconds. Drain well and mix with the onion and sausages. Cover the pan with a lid and continue to cook over a medium heat for about 5 minutes.
Add all the herbs and a tablespoon of olive oil. Season with salt and pepper.
To serve, arrange the sausage mixture on warm serving plates. Crumble over the ricotta mustia and top with the pea shoots and a sprinkling of the fennel seeds.