Place potatoes in a medium saucepan, cover with cold water, and bring to a boil over high heat.

Cook potatoes for 5-6 minutes, until tender.

Add half of the peas to the potatoes and cook for 30 seconds.

Drain the potatoes and peas.

Meanwhile, cook fettuccine in boiling salted water until al dente.

Drain the fettuccine and toss with the cooked potatoes and peas.

In a food processor, combine the remaining peas, arugula, Parmesan cheese, and garlic.

Process until smooth, scraping down the sides occasionally.

With the motor running, slowly add olive oil in a steady stream until emulsified.

Season the pesto to taste and toss with the pasta.

Melt butter in a large frying pan over high heat.

Season the scallops.

Sear scallops for 1 minute on one side, then flip and cook for another 30 seconds until golden brown.

Serve the seared scallops over the pesto-covered pasta.

Sprinkle with chopped toasted walnuts.