Heat oven to 350. Lightly spray 10 inch springform pan with cooking spray.
In large bowl, stir cookie mix, 1/3 c.malted milk powder, oil, water and egg unteil soft dough forms. Press 1/2 of dough into bottom of pan. Bake 12-13 minutes or until set. Cool completely; about 30 minutes.
Meanwhile, press remaining 1/2 dough into a 10 inch circle on an ungreased cookie sheet. Bake 12-13 minutes or until set. cool 5 minutes; remove from cookie sheet to rack. cool 15 minutes.
Spread hot fudge topping over crust in springform pan. In a medium bowl, break apart large cookie until crumbly. Stir in crushed malted milk balls. Sprinkle 1/2 of the crumbled cookie mixture over hot fudge; press lightly.
In large bowl, combine both softened ice creams and remaining 1/3 c malted milk powder until well blended. Spread ice cream mixture over crumbs in pan. Gently spread whipped topping over ice cream. Sprinkle with remaining crumb mixture. Cover with foil. Freeze at least 5