Step 1

Rinse the spinach well, drain briefly and place the damp spinach in a large fry pan. Cover and cook over medium heat until the spinach wilts, 2 to 3 minutes. Drain in a sieve under cold running water. When cool, squeeze thoroughly dry.

Step 2

Place the spinach in a food processor with 1 of the eggs. Process to a smooth puree, stopping once or twice to scrape down the sides of the work bowl.

Step 3

Place the 3 cups all-purpose flour in a mound on a work surface. Make a well in the center large enough to hold the spinach mixture and the remaining egg, lightly beaten, and place the spinach mixture and egg into the well. Using a fork, begin gradually incorporating some of the flour from the sides, taking care not to break the flour wall. When the egg is no longer runny, you can stop worrying about the wall. Continue working in more flour until the dough is no longer wet.

Step 4

Begin kneading the dough by hand, adding as much additional all-purpose flour as needed until the dough is smooth and no longer sticky, 2 to 3 minutes. Scoop up any remaining flour and pass it through a sieve to remove any large particles. Set the sieved flour aside.

Step 5

Dust baking sheets with semolina flour. Divide the dough in half. Keep one half on the work surface, covered with a kitchen towel to prevent it from drying. Set up your pasta machine alongside another work surface. Lightly flour the work surface with some of the reserved sieved flour. Using a rolling pin, flatten the other dough half into a rectangle thin enough to go through the rollers at the widest setting. Pass the dough through the rollers once, then lay the resulting ribbon down on the work surface and flour it lightly. Fold into thirds lengthwise to make a rectangle and flour both sides lightly. Flatten the dough with the rolling pin until it is thin enough to go through the rollers again. With one of the two open edges going first, pass the dough through the rollers nine more times at the widest setting; after each time, flour, fold and flatten the dough as described. After ten trips through the wide rollers, the dough should be completely smooth and supple.

Step 6

Now you are ready to thin the dough. Starting at the second-to-widest setting, pass the dough through the rollers repeatedly, setting the rollers one notch narrower each time. When the pasta ribbon gets unwieldy, cut it in half and continue rolling one part at a time until the dough reaches the desired thinness.

Step 7

Arrange the finished pasta sheets on the prepared baking sheets and cover with kitchen towels to prevent drying. Repeat the entire process with the second half of the dough. Cut the pasta by hand or machine as desired. Makes 1 1/2 lb.  dough.