Thaw spinach and squeeze dry. Chop spinach and parsley in a food processor.

Add 3 1/2 cups flour and salt to the spinach mixture and blend.

Add eggs, water, and olive oil and process until a dough ball forms.

Knead the dough on a floured surface until smooth and elastic, adding flour if needed.

Cover the dough and let it rest for 30 minutes.

Divide the dough into four portions.

Roll each portion to 1/16-inch thickness on a floured surface.

Dust the dough with flour to prevent sticking and cut into 1/4-inch slices.

Separate the slices and let the noodles dry on kitchen towels for at least 1 hour.

Fill a Dutch oven three-fourths full with water and bring to a boil.

Add noodles in batches and cook until tender, about 8-10 minutes.

Drain the noodles and serve with marinara sauce.