85g unsalted butter
1 large bunch chives or 1/2 cup tender herbs like mint, basil, or dill
1 tsp. Morton kosher salt, plus more
450g whole-milk fresh ricotta
1 large egg
2 large egg yolks
1.5 tsp. freshly ground black pepper, plus more
1/2 cup pre-grated Parmesan, plus more for serving
125 g all-purpose flour, plus more
280g frozen peas
1 lemon
Cut unsalted butter into small pieces. Place in a small bowl and chill in the fridge until ready to use. (It’s important that the butter is cold because that will help it to emulsify into the sauce later on.)
Thinly slice 1 large bunch of chives crosswise into rings. You should have about 1/2 cup. (If you’re using another herb—like mint, basil, or dill—roughly chop.) Set aside.
Bring a large pot of salted water to a boil. Cover with a lid and keep hot over low heat while you make the gnocchi.
Line a rimmed baking sheet with parchment paper or a silicone mat and dust lightly with flour.
To make the gnocchi dough, scrape whole-milk fresh ricotta onto a clean flatweave towel or a double layer of paper towels; wrap up to enclose cheese or place more paper towels on top and forcefully press down on ricotta to draw out excess moisture. If you don’t draw out moisture now, you’ll have to add more flour later, which can make for tough dumplings.
Transfer ricotta to a medium bowl. Add egg and egg yolks, salt, and several generous grinds of black pepper and mix well with a heatproof rubber spatula to combine. Mix in Parmesan followed by all-purpose flour. If dough is sticky, add more flour by the tablespoonful until dough is workable—it should still feel very light and pillowy (the amount of flour you need will vary depending on the moisture level of your ricotta—it could be 1–4 Tbsp. more).
Transfer dough to a floured work surface and knead a couple of times to bring together. Cut into 6 pieces. Roll out each piece to make a 3/4″-diameter strand, dusting with more flour as needed if dough is too sticky to work with.
Using a chef’s knife or a bench scraper, cut strands into 3/4″ pieces (flour your knife or scraper to make the process easier). Transfer gnocchi to prepared baking sheet as you go.
Now it’s time to cook your gnocchi. Bring the reserved water back to a vigorous boil over medium-high heat, then use parchment paper underneath gnocchi to gently, delicately, and carefully add gnocchi to boiling water (it’s okay if some flour gets added too).
Stir gnocchi gently with a slotted spoon to make sure they aren’t sticking to the pot or one another. Cook until gnocchi rise to the surface, about 45 seconds, then cook 1 minute more. Using a slotted spoon, scoop out gnocchi and place on baking sheet—it’s okay if you transfer some cooking water as well.
To make your sauce, pour out pasta cooking liquid, reserving 2 cups, and wipe pot clean. Set pot over medium heat and pour in 1/2 cup reserved pasta cooking liquid; add frozen peas and a big pinch of kosher salt. Cover pan and cook until peas are bright green and warmed through, about 3 minutes.
Remove lid and bring water to a simmer over medium-high heat. Using spatula, vigorously stir in reserved chilled butter a piece at a time, adding the next piece only after the previous piece is melted. You should have a smooth buttery sauce when you are done.
Slice 1 lemon in half. Cut 1 half into wedges and set aside for serving. Finely grate zest from remaining half into sauce, then squeeze in its juice. Add 1.5 tsp. freshly ground black pepper and mix well to incorporate. Add gnocchi and toss, adding up to 1/2 cup pasta cooking liquid as needed, until sauce clings to and coats gnocchi. Toss in most of the reserved chives or herbs and cook 20 seconds.
Divide gnocchi and sauce among shallow bowls and top with remaining chives or herbs and more Parmesan and pepper or crushed red pepper flakes. Serve with reserved lemon wedges for squeezing over.