Peel, devein, and rinse the shrimp under cold running water. Drain well and transfer to a bowl. Cover and refrigerate.
Heat the oven to 350 F.
In a large, heavy skillet or saute pan, heat 4 tablespoons of butter over medium-low heat.
Add 1 cup of rice to the hot butter and cook, stirring, until the rice is lightly browned. Add the 1/4 cup of parsley, 1/4 cup of shallots or green onion, and minced garlic.
In a saucepan, heat 8 ounces of clam juice, 2 cups of water, and 2 teaspoons of chicken base to a simmer over high heat. Add the hot liquid to rice mixture and then transfer to a 1 1/2 to 2-quart casserole.
Cover the casserole and bake for 35 to 45 minutes, or until the rice has absorbed the liquid and is tender. Add shrimp and 1/4 cup of pecans; cover and bake 15 minutes longer.