Peel, cored and slice apples, place in large pot of cold water with 2 tablespoon of lemon juice.
Add butter to a large pot, melt over low heat. Drain apples and add to the butter, stir to coat. Sprinkle apples with flour, cornstarch, salt, cinnamon, and nutmeg. Toss to coat. Add 1/4 cup apple cider or water.
Cover and cook over medium low heat, stirring occasionally, until apples begin to soften. Remove lid and cook another 10 minutes. Turn off heat and let stand until cool enough to place in bowl or jars for storing the pie filling.
Store up to 3 days in the refrigerator.
Make Pastry Crusts in advance. Fill, top and bake at 425 for 20 - 25 minutes, reduce heat to 375 until pastry is golden brown and filling is bubbling, an additional 30 - 40 minutes.