In a large bowl, combine 12 ounces ricotta, 1 cup of the all-purpose flour, 1 egg, and 1 teaspoon salt. Mix with a wooden spoon until the mixture is smooth.
Add up to 1 more cup of flour (you have 1 cup remaining), 1/4 cup at a time, stirring with the wooden spoon after each addition. Stop when the dough is smooth and no longer very sticky — you may not need the full extra cup.
Turn the dough onto a well-floured countertop and knead briefly (about 30 seconds to 1 minute), just until the dough comes together, is smooth, and feels slightly elastic. Add small pinches of the remaining flour only if the dough is too sticky to handle.
Form the dough into a ball, wrap it tightly in plastic wrap, and refrigerate for 30 minutes.
Unwrap the chilled dough and cut the ball into 8 equal wedges.
Working with one wedge at a time, on a lightly floured surface roll the wedge into a long rope about the diameter of your finger.
Cut the rope into 1/2-inch pieces. If desired, roll each piece over the back of a fork to create ridges. Place finished gnocchi on a parchment-lined baking sheet (lightly dust the sheet with flour if pieces are sticky).
Repeat steps 6–7 with the remaining wedges until all gnocchi are formed.
Bring a large pot of well-salted water to a rolling boil. Cook the gnocchi in batches (do not overcrowd the pot). When gnocchi are added they will sink and then float; once they float, continue cooking for at least 2 more minutes (total cooking time per batch about 3–5 minutes) to ensure they are cooked through.
Remove cooked gnocchi with a slotted spoon or drain briefly, then serve immediately with marinara or your favorite pasta sauce.