1/2 cup cold butter
1 pouch (1lb. 1.5oz) oatmeal cookie mix
14 oz. can sweetened condensed mil
2 tsp. grated lemon peel
1/4 cup fresh lemon juice (2 lemons)
Heat oven to 350 degrees. Spray bottom of 8-inch square pan with cooking spray.
In large bowl, cut butter into cookie mix, using fork or pastry blender (this is really easy if you use your clean hands). Stir in egg until mixture is crumbly. Press HALF of cookie mixture into bobbim of pan; bake 15 minutes.
In a small bowl, stir condensed milk, lemon peel and lemon juice until thick. Spread over baked crust. Crumble remaining cookie mixture over top. Bake about 25 minutes longer or until light golden brown. Refrigerate 30 minutes or until set. Cut into 5x5 rows. Store covered in refrigerator.