heat the oil in the pan you will use for baking. Add the onions and jalapenos, cook for 5 minutes on medium-high heat until the onions begin to brown. Add the garlic and cook a minute more.Add the tomatillos, reduce heat to medium and cook for 10 minutes, until the tomatillos are cooked through, but still hold their shape. Sprinkle salt over the tomatillos as they are cooking.
If using clam juice, add to the pan, turn up the heat and reduce by half. If using water, just add the 1/4 cup water without reducing.
Add the cheese and shrimp. Cook in a 425 degree preheated oven for 10 minutes.
Remove pan from the oven. Right before serving, mix in the cilantro and sprinkle with lime juice and freshly ground black pepper.