Preheat grill. Begin heating the water for the pasta.
Set out a shallow bowl, like a pasta bowl.
For each packet, cut off a length of aluminum foil about 18 inches long and then cut off a second one. Place one on top of the other (so the foil is doubled up) and put them over the bowl to create a well for the liquid ingredients.
Take one quarter of the ingredients listed, from shrimp to kosher salt, and layer them in the foil in the order shown above. Start with the shrimp, then the garlic, vegetables, and so on until you sprinkle the salt over.
Once everything is in, bring the two long sides of the foil together and fold them together to make a tight seal. Then do the same for the short sides, bringing each short side up and folded over towards the middle.
Continue until you have made all four packets.
Reduce the heat of the grill to medium-low. Put the packets on the grill and cook for 5-7 minutes, or until the shrimp is just cooked through.
While the shrimp packets are cooking, add the capellini to the water along with 1 tbsp of kosher salt. Cook according to package directions and drain.
Portion the pasta into four bowls or plates and give everyone a shrimp scampi packet to open and pour over the pasta. Garnish with fresh parsley if desired.