Mashed Potatoes with caramel

1 pound potatoes 1 pound apples, granny smith or other tart variety 1/2 teaspoon salt 2 slices bacon cut into 1/4 inch pieces 2 each onions or one large 2[...]

6 tablespoons butter 3 large onions , halved and sliced 2 tablespoons chopped fresh rosemary or 2 teaspoons dried rosemary 6 parsnips or 6 turnips or 6[...]