Put the oil in a saucepan over a medium heat, add the shallot, fennel, garlic and a pinch of salt and cook until softened. Drain the beans, reserving the starchy water from half of one can. Tip these into the pan along with the stock, green beans and cheese rind. Cook for 15 mins until the green beans are completely softened.

Stir in the peas, cook for a couple of mins more, then stir in the lemon zest and grated cheese.