1. Preheat oven to 350°.
2. To prepare crust, place first 4 ingredients in a large bowl, and beat with a mixer at medium speed until smooth. Weigh or lightly spoon 4.5 ounces (about 1 cup) flour into a dry measuring cup, and level with a knife. Add flour to butter mixture, and beat at low speed until well blended. Press crust into bottom of an 8-inch square metal baking pan coated with cooking spray. Bake at 350° for 20 minutes.
3. To prepare filling, place cottage cheese in a food processor; process 2 minutes or until smooth, scraping sides of bowl once. Add granulated sugar and next 6 ingredients (through egg white), and process until well blended. Pour filling over crust.
4. Bake at 350° for 25 minutes or until set (the edges will get lightly browned). Cool. Cover and chill 8 hours. Sprinkle with powdered sugar before serving, if desired.