Preheat the oven to 375°. Add 1 tablespoon of the butter to each of four 4-inch shallow baking dishes and mound 1/2 cup of sorrel on top. Bake for 3 minutes, or until the sorrel has melted. Remove the dishes from the oven and add 2 eggs to each. Top with 1 tablespoon of the heavy cream and bake for about 10 minutes, or until the whites are firm and the yolks are runny. Season with salt and pepper and serve.