English peas, mashed with sauteed shallots, are dotted throughout the ribbons of pasta, providing sweetness against the rich backdrop.
Blanch fresh peas in a large pot of salted boiling water until bright green and just tender, 3 to 4 minutes. Transfer to a colander with a slotted spoon. (If using frozen peas, skip this step.)
Heat oil in a large skillet over medium. Add shallot and cook, stirring occasionally, until tender, about 3 minutes. Add peas and lightly mash with the back of a spoon. Season with salt and pepper.
Meanwhile, return pot of water to a boil and cook pasta until al dente, according to package instructions. Reserve 1 cup pasta water; drain.
Add pasta to skillet and cook, tossing to coat with pea mixture. Add butter and 1/2 cup pasta water; toss to evenly coat (adding more water if necessary). Top with cheese, season with pepper, and serve.