Preheat oven to 375 degrees. Grease a 13 x 9 inch baking pan. In a medium saucepan, combine raisins, milk, lemon peel and lemon juice. Cook over a medium heat, stirring constantly until mixture begins to bubble. Remove from heat; cool slightly; set aside.
Beat butter, sugar and vanilla until fluffy. Add remaining ingredients and blend until evenly mixed and crumbly. Reserve 2 cups, then press remaining mixture onto the bottom of the baking pan.
Spread raisin mixture to within 1/2″ of the edge. Sprinkle with remaining oat mixture and pat lightly. Bake 25-30 minutes or until golden brown. Cool completely then cut into 1 x 2″ bars.