Bring 1 tablespoon plus 1 teaspoon lemon juice and 1 tablespoon water to a simmer in a small skillet or saucepan over medium-low heat. Reduce the heat to low. Whisk in 1 stick cold unsalted butter a ...
Add the pasta to the sauce with some of the water. Season with salt and black pepper, then add the lemon juice, zest, parsley and chilli. Grate over the parmesan to serve.
Transfer the pasta to the sauce, finish with Parmesan, and toss to coat. Season with salt and pepper. Arrange the pasta on the plate and garnish with a small amount of remaining lemon zest.