Step 1

Heat oven to 350°F.

Step 2

In medium bowl, mix flour, butter and 1/4 cup powdered sugar with spoon. Press in ungreased 8- or 9-inch square pan, building up 1/2-inch edges.

Step 3

Bake 20 minutes. Meanwhile, in medium bowl, beat remaining ingredients except additional powdered sugar with electric mixer on high speed about 3 minutes or until light and fluffy. Pour over hot crust.

Step 4

Bake 25 to 30 minutes or until no indentation remains when touched lightly in center. Cool completely in pan on cooling rack, about 1 hour. Sprinkle with powdered sugar. For bars, cut into 5 rows by 5 rows.