Bring a large pot of generously salted water to a boil. Boil the pasta according to the directions on the package. Drain.
Meanwhile, heat the olive oil in a large skillet set over medium-high heat. Add fennel in one layer and cook without stirring for 5 minutes — if it starts sizzling and making lots of noise, you’re doing it right. Give it a good stir and coo another 3 minutes — it will have caramelized and turned light golden brown. Add the onion and garlic to the pan and cook for 3 minutes to allow it to begin to soften. Sir in the squash, eggplant, and crushed red pepper. Cook, stirring frequently, for about 5 minutes or until the squash is cooked through.
Bring a small pot of water to a boil and add the peas. Cook for 5 minutes, or until they turn bright green and are no longer crunchy.
Return the pasta to the large pot. Add the ricotta and pesto and stir vigorously to combine and break up the ricotta — it should form a thin coat on the pasta. Stir in the fennel and squash mixture, peas, and parmesan cheese. Season to taste with salt and pepper.