Make the rolled stuffed chicken: In a skillet cook the sausage over moderate heat, stirring and breaking up the lumps, until it is no longer pink and let it cool. Transfer the sausage with a slotted spoon to a food processor, add the egg, and pulse the mixture for 30 seconds, or until the sausage is chopped fine but not pureed. In a large saucepan cook the spinach in water clinging to the leaves, covered, over moderately high heat, stirring occasionally, for 3 to 5 minutes, or until it is wilted. Drain the spinach in a colander, refresh it under cold water, and squeeze dry. Chop the spinach coarsely and sprinkle it with salt and pepper. In a skillet heat the olive oil over moderate heat until it is hot but not smoking and in it cook the garlic, stirring, for 1 minute. Add the spinach, cook the mixture stirring 2 minutes, and let it cool.
Flatten the chicken breast between sheets of dampened wax paper until it is about 1/4-inch thick, form it into a rectangular shape skinned side down, and sprinkle it with lemon juice and salt and pepper to taste. Spread the spinach evenly on top of the chicken, leaving a 1/2-inch border all around, spread the sausage mixture evenly on top of it, and beginning with the long side roll the chicken jelly roll fashion to enclose the stuffing, forming a log. Stretch the reserved chicken skin to form a rectangle 2 inches wider than the log and roll the skin around the chicken, covering as much of it as possible. Tie the rolled chicken at 1-inch intervals with the kitchen string, pat it dry, and season it with salt and pepper. In an oven proof skillet heat the vegetable oil over moderately high heat until it is hot but not smoking and in it brown the chicken. Bake the rolled chicken, seam side down, in a pre-heated 350 degree oven for 30 minutes and let it stand, covered for 10 minutes.
Make the sauce while the chicken is baking: In a skillet cook the onion in the butter over moderately low heat, stirring until it is softened, add the bell peppers, and cook the mixture, covered stirring occasionally, for 10 minutes. Add the stock and the wine and bring the liquid to a boil, and simmer the mixture covered for 10 minutes. Add the jalapeno pepper, the lemon juice, and the salt and pepper to taste and puree the mixture in a blender. The sauce may be made 1 day in advance and kept covered and chilled.
Discard the strings from the rolled chicken and cut the chicken crosswise into 12 or 16 slices. Pour about 1/3 cup of the sauce, heated, on each of 4 heated plates and arrange 3 or 4 chicken slices on each plate.
Recipe courtesy of Gourmet Magazine