Prepare the gnocchi dough: In a bowl, combine ricotta, grated Parmesan, and eggs. Mix roughly. Gradually add flour and mix until dough comes together. Transfer to work surface and knead very lightly to avoid tough gnocchi. Adjust flour amount if needed by testing a small dumpling cooked in boiling water to ensure it holds shape.
Shape the gnocchi: Form the dough into small balls. Make a small hole in the center of each ball to help them cook evenly and hold sauce.
Prepare the sauce: In a pan, cook cubed guanciale over medium heat until fat renders and guanciale becomes crispy. Add chopped spring onion, reduce heat, and cook briefly. Add fresh peas and cook quickly to keep them green and slightly crunchy.
Deglaze and reduce sauce: Add white wine to the pan with peas and guanciale. Let it reduce slightly while preparing to cook gnocchi.
Cook the gnocchi: Boil water in a large pot. Gently lower gnocchi a few at a time into boiling water. When they float to the surface, remove them with a slotted spoon and transfer directly into the sauce pan.
Finish the sauce: Toss gnocchi gently in the sauce. Add grated Pecorino Romano cheese and stir well. If needed, add a little cooking water to loosen the sauce. Season with black pepper, a pinch of chopped mint or pennyroyal, and lemon zest. Adjust salt carefully due to salty ingredients.
Serve: Plate the gnocchi with sauce. Garnish with additional Pecorino, fresh mint leaves, and plenty of black pepper. Serve immediately as a rustic and filling main dish.