Preheat oven to 400°F (200°C). Combine ginger cookies and 1/4 cup (60 mL) brown sugar in food processor. Pulse until finely ground (about 2 cups/500 mL crumbs). Stir in butter until crumbs are evenly coated. Transfer to parchment paper-lined 9 x 13-in. (3 L) baking pan; firmly press into even layer. Bake 10 to 12 min., or until crisp. Remove from oven.
Reduce oven temperature to 350°F (180°C). To make vanilla batter, in bowl, beat 1 package cream cheese with (granulated) sugar until smooth. With mixer on low speed, beat in 1 egg just until blended. Stir in vanilla. Set aside.
In large bowl, use mixer on low speed to beat remaining 2 packages cream cheese with remaining 3/4 cup (175 mL) brown sugar until smooth. Beat in 3 eggs, one at a time, scraping down sides after each addition. Beat in pumpkin puree and pumpkin pie spice just until blended.
Scrape pumpkin batter onto crust. Dollop vanilla batter over top. Using a skewer or tip of a knife, swirl vanilla batter into pumpkin batter. Bake 30 to 35 min. until centre is almost set. Cool completely on rack then chill at least 4 hr. or overnight. Transfer to cutting board and slice into 32 squares. Can be made up to 2 days in advance, wrapped and stored in fridge.
Check that you purchase pure pumpkin puree. It is different than pumpkin pie filling which is sweetened and spiced.