2. Transfer the herb mixture to a medium bowl and fold in the Parmesan cheese and olive oil.
(This can be made in advance and stored in the refrigerator for up to 3 days or frozen for longer storage.)
3. Fold in the ricotta cheese.
To make the pasta:
1. Bring a large pot of well salted water to a boil. Add the fettuccine and cook until the pasta is al dente, about 10 to 12 minutes.
2. Meanwhile, heat the olive oil in a large skillet over medium heat. Add the shallots or green garlic and cook until they begin to soften, about 2 minutes.
3. Turn the heat to high, add the chicken broth and bring the broth to a boil. Add the summer squash and zucchini, season lightly with salt and pepper and cook until the vegetables are just tender, about 5 minutes. Remove from heat, add half of the pesto and toss.
4. Drain the fettuccine, reserving 1/4 cup of the cooking liquid. Toss the fettuccine, reserved cooking liquid and remaining pesto in a large, warmed bowl. Arrange the summer squash and zucchini on top of the pasta and serve.