In a medium pot, over medium heat, add the cider, cinnamon sticks, fresh ginger, cloves and nutmeg. Stir to blend. Bring to a boil and reduce the heat to a simmer. Reduce by half and taste for seasoning. Set aside to cool. In a large bowl add the apples, lemon juice and sugar. Toss to coat and add to the cider. Refrigerate. When ready to serve the cocktails, pour the cider and apple pieces into champagne flutes (about halfway) and top with the Cava. Stir and serve.