Apple-stuffed Ostrich Rouladen with Brussels Sprouts

Rinse and scrub Brussels sprouts, cut in half and remove stems. Blanch sprouts about 12 minutes in boiling salted water and drain. Rinse ostrich roulades, pat dry and flatten if necessary. Rinse scallions and cut into 6 cm (approximately 2 1/4 inch) pieces. Rinse, quarter and core apples, cut into small cubes and sprinkle with lemon juice. Peel shallot and cut into small cubes. Spread mustard and ham slices over ostrich roulades and top with scallions and half of the apple cubes. Roll up ostrich roulades over filling and bind with kitchen twine. Heat oil in a pan, season rolls with salt and pepper and sauté on all sides. Add shallot, sauté briefly and deglaze pan with white wine. Add broth to pan and simmer gently about 10 minutes over low heat, turning rolls occasionally. Remove rolls from pan and remove kitchen twine from rolls. For the gravy, stir cream and remaining apple cubes into pan and simmer unti creamy, about 8 minutes. Stir horseradish and Calvados into gravy and season with salt and pepper. Set rolls in gravy and heat through.