1. Heat oven to 350°F. In large bowl, stir together crust ingredients. In bottom of ungreased 13x9-inch pan (Optional: use a layer of aluminum foil in the bottom of the pan that extends further than the edge of the pan.), press mixture evenly. Bake 20 minutes or until light golden brown.
2. Meanwhile, in same large bowl, stir together filling ingredients except lemon juice. Stir in lemon juice. Pour mixture over warm crust.
3. Bake 25 to 30 minutes longer or until top is light golden brown. Pour extra lemon juice over baked pan. Cool completely, about 1 hour. Sprinkle with powdered sugar. For bars, cut into 6 rows by 6 rows. It is helpful to use a very sharp knife that has been dipped in hot water.
Note: Don't overcook crust as it tends to dry out quickly. After baking bars and sprinkling with powdered sugar and cutting, wrap in plastic wrap--about 4-5 bars together so they don't dry out. Then refrigerate each package.