Put a medium pot on high heat and bring to a boil. Add your peas, half the mint leaves and simmer according to package instructions, usually 7-8 minutes.
Strain the peas and place in a high-speed blender with the metal blade on. Add the remaining 2 tablespoons of mint leaves, 70 ml from the water that the peas were boiling in, the ½ lemon Zest, any cheese or butter if using, add the salt and pepper and blend until smooth. If too thick add more water.