Bring a pot of water to a boil; meanwhile, prepare the lemon ricotta. Finely chop the mint and muddle to release its oils. In a small bowl, add the mint, lemon zest and lemon juice to the ricotta and whip with a small whisk. Refrigerate until ready to serve to allow the flavors to meld.
Once the pasta water comes to a boil, add salt and pasta and cook according to package directions. Three minutes before the pasta is set to finish cooking, add the peas to the boiling water and pasta. Drain pasta and peas and immediately toss with sauce (see below)
While the pasta is cooking, prepare the sauce. Heat a sauce pan over medium high heat. Add one tablespoon of butter to the pan and heat until it foams; and shallots or leeks and sauté, stirring the pan continuously, until the alliums are soft and just browning around the edges (4-6 minutes). Add garlic and cook until fragrant (1 minute). Deglaze the pan with the white wine, and then add the final two tablespoons of butter. Cook over medium heat until the sauce is reduced by half (3 minutes or so).
Pour sauce over the pasta and peas (if ready) or set aside into a small bowl and wipe out the pan. Bring the pan back to medium heat and add pine nuts; toast, shaking the pan continuously, until browned and fragrant (2-3 minutes). Remove pine nuts from heat and add to the pasta and peas. Add two tablespoons of butter to the pan and heat until it foams; add the mushrooms and sauté until browned around the edges. Sauté in 2 batches if necessary to ensure crispy, browned mushrooms.
Once the mushrooms are fully cooked, gently fold spinach into mushrooms, and cook until just wilted (about a minute).
Fold mushrooms and spinach into the pasta, peas and sauce. Add the juice of 1 lemon plus fresh mint and thyme, salt and pepper, to taste (I used about 3 tablespoons of mint and 1 tablespoon of thyme). Toss the pasta lightly to incorporate.
Serve immediately, topped with a dollop of lemony ricotta and parmesan cheese.