To make the shrimp and penne:In a large pot of boiling salted water, cook pasta according to package instructions.
In last 3 minutes of cooking, add shrimp and snap peas and cook until shrimp are opaque throughout and peas are bright green.
Reserve 1/2 cup pasta water; drain pasta mixture and return to pot.
Add pesto and toss to coat, adding enough pasta water to create a thin sauce that coats pasta.
Top with ricotta.
If desired, drizzle with oil and sprinkle with Parmesan.
To make the spring herb pesto:In a food processor, process 1 bunch parsley, large stems removed, 1/2 bunch mint, stems removed, 1/2 cup toasted sliced almonds, and 1/2 cup extra-virgin olive oil until smooth.
To store, refrigerate pesto in an airtight container, up to 5 days.