In a large nonaluminum saucepan, stir together the lemon juice, water and brown sugar. Peel, core and slice the apples. Stir the apples into the lemon-and-sugar mixture. Stir in the raisins. Place the saucepan over medium heat and cook until the apples are tender, about 5 to 6 minutes. Stir them occasionally and gently as they cook.
Preheat the oven to 350 degrees F.
Thoroughly butter the sides and bottom of a 10-inch pie pan.
In a medium mixing bowl, stir together the all-purpose flour, whole-wheat flour, brown sugar and salt. Use a pastry blender to cut the butter into the dry ingredients until the butter pieces are the size of small peas. This may also be done in an electric mixer on the lowest speed, but be careful not to overmix. Cut the egg yolk into the crumb mixture until it is evenly distributed.
Set aside 1 cup of the crumb mixture. Press the remaining crumb mixture into the bottom and sides of the prepared pie pan.
Spoon the apples into the crumb-lined pan and pat them down lightly. Sprinkle the reserved 1 cup of crumbs over the apples.
Dot the top of the pie with the butter pieces. Bake until bubbling and brown on top, 50 to 55 minutes.
Serve warm or cool.