What you will need:
For the fresh egg pasta:
4 large eggs
1 tablespoon water
3 ½ cups all purpose flour
½ teaspoon salt

For the spinach and cheese filling:
½ medium onion, minced
1 tablespoon olive oil
¾ cup ricotta cheese
3/4 cup Parmigiano-Reggiano cheese, freshly grated 
¼ cup mozzarella cheese, shredded
1 large egg yolk
Salt and pepper, to taste
1 bunch of fresh spinach-wash and remove stems (about 1 pound) or use frozen chopped spinach (10 oz.)

Steps to yummy goodness:
For the pasta:
1. Place eggs, water, flour, and salt in mixing bowl (counter works great as well)

2. Mix / knead for two minutes. Remove dough from bowl and hand knead for 1-2 minutes.
3. Let it rest for 20 minutes. Divide the dough into four pieces before processing with the pasta roller.

4. Roll out pasta the dough should be paper-thin, about 1/8-inch thick (you should almost be able to see your hand through it).

5. Set aside while getting the filling ready.

For the filling:
1. Place damp spinach leaves in a large skillet over medium heat. Cover with a lid and let the leaves wilt. Once wilted let cool and then chop.

2. Heat 1 tablespoon of olive oil in a small skillet. Add the onion and cook over medium heat, until translucent. Stir in the spinach and salt to taste. Cook for about one minute.

3. Transfer the spinach mixture to a medium bowl. Stir in ricotta, Parmigiano-Reggiano, mozzarella, and the egg yolk. Mix well and set aside.

4. Lay out your long sheets of pasta on a lightly floured table. Place small balls of filling, about 1 teaspoon, in a line about one inch from the bottom of the pasta sheet. Leave about 1 1/4 inches between each ball of filling. Fold over the top of the pasta sheet, lining it with the bottom edge. Seal the bottom and 2 open sides with your finger. Use a ravioli cutter to cut out the individual raviolis. Place the ravioli on a large plate.

5. Boil a huge pot of water with salt. Add in the ravioli and cook for about 5-6 minutes. Strain and serve with the sauce of your choice.

.: Side Notes :.
If you have a Kitchen Aid Mixer you can use that to mix the pasta dough just make sure to use the hook attachment and keep the speed on low

Feel free to add any herbs you like to the filling, when I want to change things up I normally add a little basil, rosemary or whatever else I have on hand.