Heat 3 tablespoons oil in a saucepan and saute spring onions on low heat 5 minutes, taking care they do not burn.
Add frozen peas, stir and cook 2-3 minutes. Season with salt and add water. Simmer peas 30 minutes, adding more water if necessary.
Cut the bread into cubes. Place in a bowl and season with fresh or dried herbs to your taste. Add a little olive oil and mix well with your hands.
Place the bread cubes on a baking tray lined with baking paper. Toast under the grill a few minutes until evenly browned.
In a bowl, combine the mascarpone and grated Parmesan and mix well with a fork.
When the peas are done, blend the soup until smooth. If it is too thick you can add a little more water. Season with salt and pepper.
Divide the soup between bowls. With two teaspoons make little balls of the mascarpone mixture and place in the centre. Decorate with croutons and a drizzle of olive oil.