Preheat oven to 350°.
To prepare crust, lightly spoon flour into dry measuring cups; level with a knife. Heat a nonstick skillet over medium-high heat. Add flour to pan; cook 5 minutes or until light brown, stirring often. Remove pan from heat. Transfer flour to a bowl; cool completely.
Combine cooled flour, 1/2 cup brown sugar, and salt in a food processor; pulse 5 times or until combined. Add chilled butter; pulse until mixture resembles fine meal. Press 1 cup of flour mixture evenly into the bottom of a 13 x 9-inch baking dish coated with cooking spray; reserve the remaining flour mixture. Bake at 350° for 10 minutes or until crust is lightly browned.
To prepare filling, spread pumpkin in an even layer on several layers of paper towels; cover with additional paper towels. Let stand 5 minutes.
Combine granulated sugar, 1/2 cup dark brown sugar, and cream cheeses in a bowl. Beat with an electric mixer at medium speed 2 minutes or until smooth. Scrape pumpkin into bowl using a rubber spatula. Add egg substitute, cinnamon, vanilla, allspice, and egg; beat until smooth. Scrape batter into baked crust.
Combine reserved flour mixture and pecans in a small bowl; sprinkle with 2 teaspoons water. Squeeze handfuls of topping to form large pieces. Crumble over filling. Bake at 350° for 40 minutes or until filling is firmly set. Remove from heat; cool in pan on wire rack to room temperature. Cut into 12 portions. Serve at room temperature.