Rinse the duck and dry with paper towels. Brush the mustard over the skin, then wrap in plastic wrap and refrigerate overnight.
Next day, season the duck with salt and pepper inside and out. Rub the crushed garlic on the inside of the cavity.
Cut the apples into slices. Stuff the duck with the apple slices, then close the cavity with toothpicks. Preheat oven to 170 degrees C.
Place duck breast side up on a baking tray. Cover with foil and roast 1 1/2 hours. Remove foil, brush the duck with honey and paprika, and roast uncovered another 30 minutes at 220 degrees or until golden brown.