Preheat oven to 425 degree Fahrenheit degrees.
Layer the pasta shells in a single layer in the baking pan.
Add the milk, water, salt and spice, mix well.
Add the marinara sauce and oil, mix well again so the sauce and oil blends well with the pasta.
Finally add the spinach leaves and green peas to the pan, stir into mix with the rest of the ingredients.
Place the butter (if you are using melted butter you can add early with the oion top of the baking pan.
Cover the pan with foil and bake in the preheated oven for about 30 minutes.
After 30 minutes of baking, remove the foil carefully, (do not sir the contents at this poinand bake for another 20 minutes or until the pasta is baked well (you may also bake for few more minutes if you wish (and add some shredded cheese too if you wish sto lightly brown the top, but make sure to watch to avoid burning of pasta.).
Stir and serve, enjoy the easy, delicious and healthy no boil baked spinach pasta!