In a large mixing bowl, cream the butter, sugar and vanilla. Add eggs, one at a time, beating well after each addition. Combine the flour, cinnamon, nutmeg, salt and baking soda; gradually add to creamed mixture and mix well (batter will be stiff). Stir in apples until well combined.
Spread into a greased 13-by-9-by-2-inch baking dish. Bake at 350 degrees for 40-45 minutes or until top is lightly browned and springs back when lightly touched. Cool for 30 minutes before serving.
Meanwhile, in a small saucepan, combine brown sugar and butter. Cook over medium heat until butter is melted. Gradually add cream. Bring to a slow boil over medium heat, stirring constantly. Remove from the heat. Serve over the cake.