Bring a large pot of water to a boil for the pasta.
Heat a large skillet over medium heat with 2 turns of the pan of olive oil. When hot, add butter to oil. When it foams, add shallots or onions and garlic, and season with salt and pepper. Stir 3 minutes then add stock; boil and reduce heat to a low simmer.
Salt pasta water, drop pasta to cook to a minute shy of al dente.
Add peas to simmering stock and cook 3-4 minutes then stir in the ricotta and warm through; add thyme and lemon zest. Reserve 1/2 cup starchy, pasta water then drain pasta. Add pasta to sauce along with the starchy water and grated cheese; toss to coat. Add most of the parsley and mint, and transfer to serving bowl.
Top with drizzle of EVOO and remaining mint and parsley.