Boil the Stellini pasta for 5 minutes; strain and set aside. The pasta will only be partially cooked and will finish cooking in the oven.
Preheat the oven to 350F.
Fold four 18-inch-long pieces of foil in half; unfold and coat inside with cooking spray.
Place 2 cups spinach in center of 1 half of each piece of foil.
On top place 1/4 cup of the stelline.
Place 1 tablespoon of the reserved pasta water on top of the stelline.
Combine the shrimp, 1/4 cup cilantro, oil and 3/4 teaspoon salt in a bowl.
Evenly divide amongst the 4 foil packets and place on top of the stelline.
Fold foil to close and crimp edges to seal forming a pocket. Be sure to leave at least a 2” space all the way around between the food and crimped edges to allow for the steam to build up inside.
Bake for 15-20 minutes or until the shrimp is pink.
Remove from the oven and carefully open up (watch your face from the steam!).
Set the foil right on the plate and eat out of that or you can scoop up the contents and plate that way.