Heat oven to 350°

In a 13 inch by 9 inch pan, combine flour, sugar, lemon peel.

Cut in butter until it resembles coarse crumbs. (Can be done in a food processor.)

Pat crumbs evenly and firmly in pan.

Bake 20-25 minutes until lightly brown.

In food processor, combine topping ingredients.

Cover and process 5 seconds.

Scrape down sides and process 5 seconds more.

Pour over partially baked crust.

Bake 20-25 minutes until lightly brown.

Cool in pan over wire rack.

Cut into squares (2 inches by 2 inches).

Sift powdered sugar overtop while still warm.