Turn oven to 350 degrees. In a large mixer bowl beat peanut butter and butter with electric mixer on medium speed about 30 seconds. Add brown sugar and beat until fluffy.
Add eggs and vanilla. Beat well.
In a medium mixing bowl stir together flour, wheat flour, baking soda, and salt. Gradually add flour mixture to peanut butter mixture, beating till well mixed.
With a wooden spoon, stir in quick-cooking oats and the chopped apple.
Put 1/4 cup mounds of dough about 4 inches apart on ungreased cookie sheets Flatten each mound slightly.
Bake in the 350 degree oven for 12-14 minutes or till edges are firm. Let cool on cookie sheet for 1 minute. Cool on cooling rack for 20 minutes. Makes about 20 large cookies.