This dish is best made with a Camembert-style Irish cheese such as St. Killian, from Carrigbyrne Farmhouse Cheese, Enniscorthy, County Wexford. Like other white rind cheeses, this is delicious deep-fried in beer batter and served with tangy Cumberland Sauce, which should be prepared a day in advance to let the flavors meld.
To make the Cumberland sauce: With a vegetable peeler, peel strips of zest from the orange and lemon. With a sharp knife, shred the zest as thinly as possible. Put the zest into a small saucepan and cover with cold water. Bring to a boil, then reduce heat to simmer and cook for 5 minutes, or until the zest starts to soften. Drain and set aside.
Squeeze the juice from the oranges and lemon into a small saucepan. Add the jelly, ginger, and mustard, and bring to a boil. Cook for 5 minutes, then reduce heat to simmer and cook for 10 minutes, or until the mixture is reduced by half. Transfer the sauce to a small bowl and stir in the reserved zest. Refrigerate for at least 24 hours and up to 3 weeks. Makes about 1 1/2 cups.
To make the fried cheese: In a large bowl, whisk together the flour, beer, salt, and oil. There should be a few small lumps. Cover the bowl with plastic wrap and let stand in a warm place for about 3 hours. Stir in the egg yolk. In a small bowl, beat the egg white with an electric mixer until stiff peaks form. Fold into the beer batter.
Cut each round of cheese, rind and all, into 8 pie-shaped slices, then cut each slice in half. In an electric skillet or deep fryer, heat the oil to 325°F Dip the cheese pieces, one at a time, into the beer batter. Drop into the hot oil, and cook, turning as necessary with a wooden spoon, for 1 to 2 minutes, or until golden brown. With a slotted spoon, remove each piece as soon as it's browned and drain on paper towels.
To serve, spoon the Cumberland sauce into small ramekins or dishes and place in the center of 4 salad plates. Arrange the mixed greens around each ramekin and place 8 pieces of cheese on top. Serves 4.