Heat the oven to 400°F. Place the potatoes on a baking sheet, poke all over with a fork, and bake 55-65 minutes, until very tender when pierced with a knife. Let cool until warm enough to handle.
1/2 pound russet potatoes
To microwave potatoes instead, prick all over and heat for 5 minutes. Flip, then heat another 3-5 minutes, until easily pierced.
Cut the potatoes in half and scoop the flesh into a bowl, discarding the skins. Pass the potato through a ricer or mash until smooth.
Add the flour and 1/2 teaspoon salt to the potatoes. Add the egg and gently mix until a soft dough forms. If the dough is sticky, add a little more flour, 1 tablespoon at a time, until it holds together but remains tender.
1/2 cup all-purpose flour, 1/4 teaspoon fine sea salt, 1 large egg yolk
Turn the dough onto a lightly floured surface. Divide into 4 portions and roll each into a rope about 3/4-inch thick. Cut into 1-inch pieces. Roll lightly over a fork or gnocchi board if desired and place on a floured tray.
Bring a large pot of salted water to a boil. Cook the gnocchi in batches for 2-4 minutes, until they float to the surface. Transfer to a plate with a slotted spoon. Reserve 1/2 cup of the starchy water.
Heat the butter in a large skillet set over medium heat. Add the shallot and cook 2-3 minutes, until softened. Stir in the garlic and cook 30-60 seconds until fragrant.
2 tablespoons unsalted butter, 1 small shallot, 1 clove garlic
Sprinkle in the flour and cook about 1 minute, stirring constantly. Slowly whisk in the vegetable broth until smooth.
1 tablespoon all-purpose flour, 1/2 cup vegetable broth
Stir in the lemon juice, lemon zest, and heavy cream. Simmer 1-2 minutes until slightly thickened.
2 teaspoons lemon juice, 1 teaspoon lemon zest, 1/2 cup heavy cream
Add the parmesan and stir until melted. Add the peas and cook 1-3 minutes until heated through. Season with salt and pepper.
1/4 cup freshly grated parmesan, 1 1/2 cups fresh or frozen peas
Add the cooked gnocchi to the skillet and gently toss to coat in the sauce. If needed, add some of the reserved water to thin out the sauce. Remove from the heat, stir in the parsley and dill, and finish with additional parmesan if desired.
2 tablespoons chopped flat-leaf Italian parsley, 1 tablespoon chopped fresh dill, 1/2 teaspoon fine sea salt, 1/4 teaspoon ground black pepper
Notes
If doubling the recipe, use 1 whole egg, not 2 egg yolks.
Freeze gnocchi on the tray, then transfer to an airtight container and freeze for up to 2 months. Cook from frozen.