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[...]

4 ounces bacon , cut into 1/2-inch pieces 2 tablespoons bacon fat 2 tablespoons butter 8 ounces turnips , peeled and cut into a 1/2-inch dice (about 1 1/2[...]