Combine these three ingredients in a medium mixing bowl, and stir well. Press crumb mixture into bottom of a 9 x 13 pan and set aside.
In a large mixing bowl, whip the butter until fluffy. Add powdered sugar, mixing until smooth. Beat in the unwhipped cream to make mixture spreadable. Spread carefully (I use a spoon dipped in water) over the crumb crust.
Arrange peaches over filling. Beat remaining whipping cream and powdered sugar until soft peaks form. Spread over peaches. Cover and chill for at least 2 hours. If desired, coarsely crush a few cookies (without the filling) and sprinkle over the top.
(note from Mom I make the middle layer 1.5 times. It makes it easier to spread, and it’s our favorite part of the recipe.)