Lemon squares - the best recipe ever!!!

1 1/2 sticks unsalted butter
2 cups all-purpose flour
1/2 cup light brown sugar packed
1/2 tsp salt
4 large eggs
1 1/2 cups sugar
3/4 cup lemon juice
1/3 cup all-purpose flour
3 tbs confectioner's sugar
Preheat oven to 350 degrees.
Cut butter into 1/2 inch pieces. In a foot processor, process all ingredients until mixture begins to form small lumps.
Sprinkle mixture into a 9X13X2 baking pan and with a metal spatula press evently onto the bottom of the pan.
Bake the shortbread in middle of oven until golden about 20 minutes.
While shortbread is baking, prepare topping by whisking together eggs and sugar. Combine well. Stir in lemon
juice and flour. Pour lemon mixture over hot shortbread. Reduce oven temperature to 300 degrees.
Bake in middle of oven until set, about 30 minutes.
Cool completely in pan and cut into 24 bars. Bar cookies keep, covered and chilled,