pasta
Bring 4 cups of water to a boil. Add spinach and cook just until wilted, about 2 minutes. Remove and drain. When cool, squeeze out excess water. Reserve the spinach water.
Puree spinach with 2 eggs. Set aside.
Mound flour on a cutting board. Make a well in the center, add the 2 additional eggs and spinach puree. Slowly add flour into the center as you mix. I use my hands, but a fork is fine. Add more flour to board if necessary and knead into a smooth dough. Add a little reserved spinach water if it's too dry. Roll into a ball and cover with a damp towel. Rest dough for about 15 minutes.
Roll out dough to about ΒΌ-inch thickness and cut into desired shape by hand or machine. Allow noodles to air dry for several minutes.
Bring water to a boil. Add salt then carefully drop in noodles in small batches. Stir and return to a boil. Fresh pasta cooks quickly, in about 3 to 4 minutes. Drain and serve.
sauce
Combine all sauce ingredients in a food processor. Pulse until chopped.
Transfer to a medium saucepan and cook over medium heat until spinach wilts, flavors blend and sauce is thoroughly heated. Add a bit of pasta water if sauce seems too thick.